Dear Jonathan
There were 3 men named James Grant in the 42nd Foot at this time. One of these fought in the 1815 campaign in No.5 Company and was wounded at Quatre Bras (along with much of the regiment) two days before Waterloo.
Alas, at present I don't have any way of proving which James Grant this was - if he was your man from Urquhart or one of the other two.
Interestingly, there was a Malcolm Grant in Number 9 company, listed as from Urquhart, who was killed at Quatre Bras. A relative perhaps?
Sorry I cannot be more definitive.
Martin