Am I going to be okay ? NHS GRS London

I’ve been on a video consultation with a man from the NHS and we discussed what surgeries I’m interested in

I’m planning on having GRS

He told me that when I hit 12 months on HRT he will send have a video call with me again and send off a letter to a London hospital that cover GRS

He mention that the senior surgeon DR Bellringer would be 1 of the available surgeon

I’m from wales so travel wise he said London would be the best option

He mentioned things like dilation and getting in contact with the gender nurse clinician

So my questions are what are the surgeons in London and are they good ? Will I be In safe hands ?

My other question is what should I do to prepare :make sure the surgery goes well?

The man also told me that 80% of surgeries are successful

And that 20% aren’t how come that number is so large ?