I pay £50 for a call out, half price on zone day. They do have to come quite a long way though. However, having just had the bill for my horse going up for a rescan I was stunned, £180! It has gone up rather a lot, but they have moved to a bigger practice, so the price going up isn't really a surprise.
my equine clinic vet charges £50.00 for about 10 miles away i think but the same practice also has a mixed practice a mile away which also charges £50.00 so standard call out. I always take my horses to the vet unless they cannot travel. BTW OP my vet will let clients jab their horses for tetanus at home, cost £11.00 for vaccine but it wont get written up in your passport, I asked for a livery of mine a couple of weeks ago.
It also seems vets are more and more expecting payment at time of vist. In a recent newsletter from my vet it said vets would now be carriyng card machines so can take payment there and then
I think my vets are about £18 for pre-arranged call out. They do a deal though where if you book 3 horses to be treated in one call it is free, which I've used for both jabs and teeth this year.
I have no complaints about my vet's bills or service
The OP lives in Hampshire and therefore has a large number of equine vets to choose from. This creates a truly competitive market between practices and helps keep fees pegged to costs. As both quotes are within the same ball park then I suspect your paying the going rate. Many clients seem to forget that it is the aim of private practices to make a profit!