Which vets do you use normally? Not Matthews at Syston is it? I know he only does Bucks.
We've had quite a few does spayed at the Park Vets on Saffron Lane. Helen, one of the vets is good with exotics (rabbits). The spay costs £70.
There is also Chine House at Sileby. They have a small animals expert there, but I'm not sure of the cost.
Alternatively, Jill will know someone