For anyone in North Wales, particularly somewhere near Wrexham, I can recommend Vets4Pets Wrexham.
Two years ago, just a few months after we adopted my 2 sows, one of them, Meemee, started bleeding. We brought her to a vet here near where we live, but the vet there told me some piggies bleed when they're in heat and it will just stop after a few days. But hubby and I were a bit hesitant to just ignore it. So the next day, we took her to Vets4Pets Wrexham even if we live in Denbigh. When we arrived, the vet examined her right away, did some x-ray and ultrasound and they found out her ovaries were inflamed. They advised her to get spayed. So that same day, Meemee was spayed and we took her home in the afternoon. She hasn't had any problems ever since.
Hubby said that in the past, he had also took his past piggies in Vets4Pets Wrexham and they found them very knowledgeable with small animals. The vet even told us she has guinea pigs herself too and that made us feel safe.