Different costs of operating. One practice may use untrained staff and do the hip scores radiographs on the same table they use for consulting. The other practice may be staffed by qualified nurses, digital radiographs, full anaesthetic monitoring etc etc.
Very few practices are directly comparable. I know where I'd rather my dog had an anaesthetic.
One may include the BVA fee, one may not. One may have erroneously quoted for both hips and elbows and the other just elbows.
Although sometimes it does, mine was done under sedation rather than a general by a practice that does a lot of them. She did go with a friend who took 5 dogs but that was a little over £100 all up. Because they do a lot of them the X-rays were good.
In a word Yes..! I used to live in Suffolk and i would only use one vet in the whole county due to their prices..!
Treat vets like insurance companies, You get the odd good one but most are just after your money.