@RubyGrace I'm really sorry but I don’t know of any. There's a vet locator on the forum so you could see if there is any vets on there.
We have a wonderful guinea pig vet down here in Northampton called Simon Maddock. He's based at the Cat and Rabbit Care Clinic and is very experienced with dental issues.
I know it would be a really long journey for you to come to see him, so he will speak to your vet to offer his advice on how to tackle your piggys teeth. I'd definitely recommend asking your vet to contact him.