Hmmmm a tough one! I was also thinking of a Tag Heur which is about £850....I said we could try it on when we go to try wedding rings to see what he thinks as he wants to buy one for himself. Little does he know!
What about a track day, trip somewhere, a nice but cheaper watch, an 'experience' of some description, a day out and buy him something whilst there?
Good luck! At least you have a big budget so there should be lots of options!