I would suggest getting more than one opinion, and seeking out Doctors that have had experience helping singers before. There are a few in my area that I could research for you (I have had several friends who have had issues, and sought help). But that won't help you any if you live in London.

In any case, from all I have personally heard, the potential prognosis ranges anywhere from "No, you'll never sing again", to "No worries, take a few steps and all will be right forever", and everything in between.

As an aside, Celine Dion had similar problems. Her Doc told her to *not* use her voice (not even for speaking) when she was on tour, and to warm up well before any performance. She would tap out in code (something like 1 for yes and 2 for no) with her Mom on the phone instead of speaking.