£89
I had quotes from two other vets though, one £125 and the other £70-80 depending on rabbit size as bigger rabbits require more medication/anaesthetic during).
ETA above is for spay this April, last April when I got Harvey I paid £79 for neuter and asked about spay prices so I could start saving for when I got Harvey a girlfriend, and they said £120, so within a year their price randomly dropped, no change of ownership or anything :s but good for me! Although I feel Harvey's neuter was rather pricey!