Thanks guys, I really appreciate the welcome and the very helpful comments. I've since had another meeting with another member of the urology team - consultant urological surgeon. He said the score I have shows some animal like cancer but also some monster like cancer. He confirmed that the position of my tumour is very unusual - only 5% of patients have anterior tumours.
He said it's probably been there growing for 2-3 years. My genetic history (lots of cancer) and the location and poor prognosis of of other treatments suggests (as Barry and Ulsterman suggest) that surgically removing whole prostate is the best option. Also I am young. Only 10% of patients are about my age. Side effect - erectile disfunction is likely, will not be able to ejaculate, may leak urine - so do pelvic floor exercises. He's confident he will save the nerves - 95% chance of complete cure (so long as it hasn't metastasised).
He's confident that radiotherapy for my (genetic) cancer will only be a temporary fix - it will come back and it will spread - the radiotherapy will severely damage the organ, will likely make me incontinent and will likely damage the bladder. It will also make future treatment very difficult. Like Barry said, the organ then becomes inoperable. The consultant said it was then butchery not surgery to remove it. The location makes cryotherapy very difficult (needles may not reach) and again it will likely return somewhere else. His advice is don't mess around - get the whole prostate removed.
As my wife and I were leaving the hospital we met a guy who was operated on 6 weeks ago - it was great to meet him - a golfer, who showed me his 5 small scars from the keyhole surgery.
So next I'm getting a PSMA PET test done, which may show the cancer having spread. If it hasn't, then I think I just go ahead with surgery, a date for which is already being arranged. Thanks again guys.