Found this for you wiggal:
http://www.rcvs.org.uk/Templates/Internal.asp? NodeID=92575&int2ndParentNodeID=89737&int1stPa rentNodeID=89642
Personally, I would pay them and let them take the stiches out for the cat.'s sake and when you are satisfied that the cat is OK I would then inform the vets that you are reporting them with a view to suing them.
The cat's well-being is the prime issue at the moment. Once your friends are happy that the cat is on the road to recovery, then they can do their utmost to pursue the negligence of the vet.
If the vet's refuse to treat the cat even if your friends pay, I would take it to the local Cat's Protection League, explaining the situation. They have vetinary nurses who can take stitches out. They will not turn it away.
Come to think of it, that would be my first course of action.
Hope all goes well.