Bill,
Thank you very much, I forgot about this account.
It is a rare detail. Several other British officers, sergeants, and corporals, who fought at Albuera, don't mention that the French first rank knelt:

Charles Leslie (29th Regiment, in the same brigade with 48th):
An Old Comrade, “The Twenty-ninth at Albuera.” // The United Service Journal, 1835, part 3, p. 219–221.

Moyle Sherer (34th Regiment):
Sherer, M., Recollections of the Peninsula. London, 1824, p. 159-160.

Edward Blakeney (battalion commander, 7th Fusiliers) and General Lowry Cole:
Wade, T., Cole, L., “Sir Lowry Cole and Colonel Wade on the Movement of the Fourth Division at the battle of Albuhera.” // The United Service Journal, 1841, part 1, p. 538–540.

Jonh Spencer Cooper (lance corporal, 7th Fusiliers):
Cooper, J. S., Rough Notes of Seven Campaigns in Portugal, Spain, France, and America, During the Years 1809-10-11-12-13-14-15. London, 1869, p. 60–61.

Best wishes,
Alexander