Hi Loose rivets,
I'm not a doctor but for me personally I would have a biopsy if it was recommended to me. Don't worry about whether the Dr also owns the clinic. In the overall scheme of things, that shouldn't be a deciding factor in my point of view.
Gingernut and obgraham always seem to give sound advice from my observations and they seem to be suggesting that consulting a specialist is the way to go at this point.
Good luck with it all.
VH-MLE