Backpacker - Offshore medicals - certainly in the UK, if the AME is not UKOOA accredited, he can't do it.
The UKOOA examinations are pretty much similar with (off the top of my head) the addition of Keystone eye tests, audiometry is required for the UKOOA (but not for PPL unless IMC/IR), and it's possible the urinealysis is slightly different. And there's no ECG as standard on the UKOOA.