that does seem rather steep!
altho ive not done a landrover timing belt at work, ive done plenty of other makes and we charge anywhere between 190 and 250 ish for a timing belt replacement including guide pulleys and tensioners that come in the kit.
its a bit late now tho as the garage has done the work and will want paying for it.
its always best to get an estimate before major jobs, as has already been said.