The personnel cavalry escort for Omar Pasha (watercolour in the UK National Army Museum collection), were from the 3rd Corp Cavalry, and were from 1851-1853 dressed in purple jackets. However, in this particular painting are shown in light blue jackets, which were for the 6th Corps (1851-1853).
Right - "Turkish Soldiers in Summer Uniform" (1853) painted by Count Amadeo Preziosi, in Constantinople.
The Ist Lancers are known from 1840, and the particular uniform, with red lapels which appeared in the 1850s; however, it appears that the regiment around 1853 returned to its pre-1840s version prior to the Crimean War.
Right - This 1855 sketch, from - General Vanson: Album ‘Crimee’, vol. 2. Bibliotheque de la Musee de l’Armee, Paris , shows an Ottoman cavalry officer, wearing a shell jacket with lapels. This particular uniform appeared at an earlier date during the 1840, and was a key feature of the 1st Lancers' dress in that period.
 MaxNechitaylov. Turkish Uniforms of the Crimean War (1853-1856). Military Крым. 2008. № 8. С. 3-16; № 9. С. 3-11: pg72.
The Turkish Irregular 'Cavalry Gallipoli', 1854 (watercolour in the UK National Army Museum collection) are described as "Brightly coloured Turkish cavalrymen who were encountered by Markham when his unit stopped off at Gallipoli while en route to the Crimean War (1854-1856) (Watercolour by Second Lieutenant William Thomas Markham (1830-1886), 2nd Battalion, Rifle Brigade, 1854). These appear to be mounted Ottoman Bashi-Bazouks.
The 18th century beginnings of the Ottoman Bashi-Bazouks, were originally describing the homeless beggars who reached Istanbul from the provinces of the Ottoman Empire, the term Bashi-Bazouk was later applied to all Muslim subjects who were not members of the imperial army, but whom were employed in formed bands of mixed mounted and foot troops attached to the army but under independent officers and providing their own weapons and horses. They appeared at the end of the 18th century and fought in Egypt against Napoleon. During the Crimean War the allied generals made fruitless attempts to discipline them.
Sone 4,000 Bashi Bazouks, Turkish irregulars, were placed under the command of Lieutenant-Colonel (later Major-General) William Fergusson Beatson (1804-1872).
The Bashi Bazouks earned an unsavoury reputation for pillage and indiscipline during fighting in Silistria. In spite of the subsequent attempt of Beatson to instil order into the irregulars brought into British pay, his efforts were undermined by the refusal of Lord Raglan to make use of them, and the regiment is said to have been disbanded in September, 1855  ; however, this is not entirely correct :
Beatson was to form an irregular cavalry division of about 4,000 men in Bulgaria, called the “Osmanli Irregular Cavalry”, or ‘Beatson’s Horse’. This was accepted for formation in 1854. And its formation coincided with the formation of the Turkish Contingent. And it was attached to then in September, 1855. However, between July 1855, and July 1856, the “Osmanli Irregular Cavalry”/‘Beatson’s Horse’, only ever mustered 1,500 (according to Capt. Edward Money). These troops were stationed in Canakkale (Dardanelles). At the same time, as the formation of the Turkish Contingent, a separate (another) “Osmanli Irregular Cavalry”, was also formed. After Beatson’s recall (in 1855), the two troops of “Osmanli Irregular Cavalry”, merged and an “Osmanli Irregular Cavalry”, continued to function during the Crimean War .
Right - A picture of Captain of Beatsons’s Horse Edward Money. In his book he reported (p. 59-61): “... Before leaving the Dardanelles, I had ascertained where I could get my uniform at Constantinople, ... set Mr. Lawrie, the tailor, and his myrmidons to work. I have said that no two at the Dardanelles were dressed alike: this was more owing to some having got uniforms of former services, varied according to their tastes, than to the fact of no regular or efficient dress being in existence. The uniform I got made, and which was what General [W.F.] Beatson had devised, was as follows: – A dark green cloth frock coat fastened with hooks up one side of the chest, and totally without collar of any kind, as also without ornament beyond a beading of gold lace to correspond with the small brass buttons running up one side of the chest – a pair of scarlet breeches, with a broad rich gold stripe running down the side of the leg – patent leather jack-boots with large brass spurs, and a cap, without peak, of scarlet cloth with gold band and braiding." The Edward Money book reports (p. 59-61): "... The dress, which may be seen in the illustration facing the title-page, ... ; the coat especially was in good taste and very comfortable for hard work. I found, however, I could not stand the want of a peak to the cap, my eyes could not support a Turkish sun without it, and, as I had seen much licence in uniform was allowed, I had one put on."
The Edward Money book, further reports (p. 59-61): "The uniform was soon finished, and, as I found all my luggage at Constantinople, I was once more in decent attire with the comfort of a clean shirt on my back. I found the naked neck at first very uncomfortable, (no collar or neckcloth was allowed, and the coat was cut down very low,) while it certainly looked peculiar."
The Edward Money book, further reports (p. 59-61): "For some weeks, till I got accustomed to it, I was continually getting stiff necks. After suffering some time from this, I, on my return to the Dardanelles, put on a collar and black neckcloth. General Beatson happened to see me when thus attired – “What’s that bit of carpet you’ve got round your neck, Captain Money?” he said. “It’s a simple neckcloth, sir.” “Take it off, I beg; when the neck is covered, it quite destroys the character of the uniform. I’m not particular generally as to dress, but I’ll allow nothing about the throat, which should be as naked as your hand.” I found out afterwards, this was his hobby, differing somewhat from Sir George Brown’s, who killed his men by strangulation. I obeyed him of course, and of course got another stiff neck. I became accustomed to it, however, at last, and eventually thought with him that it looked well. From disliking I got to like it so much, that when later at Shumla under another Commandant [General Smith] neckcloths became the fashion, I always wore my throat bare!..."
Right - This illustration from the National Army Museum collection, shows "Bimbashi Yusuf Bey A.D.C. to General Beatson commanding the Bashi Bazouks." This figure wears an identical uniform to that of CAPT. Edward Money .
 Edward Rice. Captain Sir Richard Francis Burton: A Biography. Da Capo Press: 344. "Beatson ... who wore a gorgeous uniform blazing with gold to impress the Turks. The Bashi-Bazouks wore similar uniforms."
 Mary S. Lovell. A Rage To Live. Hachette UK (1998): “All the British officers who served with the Turkish forces wore ostentatious uniforms in order to maintain the respect of the men under their command, Richard [ ... Richard Francis Burton 1821-1890 ... ] was no exception; ‘I was in the gorgeous Bashi-Bazouk uniform, blazing with gold, ‘ he said. Beaston’s jacket was said to be so stiff with gold embroidery that it could stand up of its own accord.
 Mesut Uyar, Edward J. Erickson. A Military History of the Ottomans: From Osman to Ataturk: 173.
 There is another Beatsons’s Horse (Beatson's Irregular Horse), which was formed in 1857-60, again by Beatson, this unit was part of the Central India Horse (later 21st King George V's Own Horse). They were formed at the start of the Mutiny of 1857, and later also disbanded (Wood, Evelyn. From Midshipman to Field Marshal. London : Methuen, 1906: 167-175).
 Candan Badem. “The” Ottoman Crimean War (1853 - 1856). BRILL, 2010: 262.
Right - Identified as "Artillery Turkish Contingent", this is an officer in a former East India Company troop of horse artillery that was grouped with Beatson's Horse (Osmanli Horse) .
 In HANSARD documents relating to the Parlementry Case, involving Gen. Beatson in 1856 (THE CASE OF GENERAL BEATSON. HC Deb 22 July 1856 vol 143 cc1238-66), there is a mention of "Major Copely, of the Osmanli Horse Artillery", being part of the Beatson’s Horse.