Finch’s cavalry brigade was at the Battle of Nicopolis, normally referred to as Alexandria in British accounts. It formed part of the second line, left of centre behind the large sandbank that dominated the middle of the British position. At best no more than 450 men were mounted; the remainder acted dismounted. The British cavalry, poorly mounted and too few to withstand the French dragoons, was not committed during the fighting.
The strength of the cavalry brigade on 7 March (parade strength before landing) was 1,213 as follows: 11th Light Dragoons (one troop), 62; 12th Light Dragoons, 543; 26th Light Dragoons, 447; and Hompesch's Mounted Rifles, 161. A return dated 25 March showed the situation had improved slightly as it recorded some 510 cavalry (11th, 50; 12th, 380; and 26th, 80), which would appear to be all the mounted horse. They were sent to the Nile and took part in the advance to Cairo.
[The above is largely taken from Mackesy, 'British Victory in Egypt', London 1995, quoting a various sources]