The Hompesch Mounted Rifles are another of the émigré units serving with the British in Egypt, and the only such cavalry unit. Raised in 1798 by Baron Charles de Hompesch-Bolheim, a Prussian in British service, chiefly from German, Austrian and French nationals the regiment served in Ireland, Ferrol and Cadiz before sailing to Egypt. The unique shako gives them the honour of being the wearer of headwear type 16 in this army.
Another interesting snippet related to this regiment that my friend Keith pointed out in a comment a few days back is that its founder, Thomas Graham, had a deeply personal reason to detest the Revolutionary forces of France. Although somewhat sympathetic to their ideals at first, when his wife died in France and was being repatriated to Britain, a group of Revolutionary soldiers opened the coffin and disturbed the body, changing his view of the Republican cause. His military career became his means for revenge against the actions of those men.