Nick,
Good that you have made your reasoned treatment decision.
You don't show where you are located in the UK but I don't know why anyone would have contemplated paying 15K for HIFU when they could easily fly or get transport to London, maybe stay a night or two in a hotel and return to wherever after treatment for a fraction of this sum using the NHS. I live in Devon, close to the border with Cornwall, so something like 220 miles from London hospitals and had my second HIFU during the Covid Pandemic in 2021. As the hospital wanted me to minimise contact with others, they arranged for me to be taken by car to London early in the morning, have my HIFU and then return me to Devon by car the same day. If this had happened outside of COVID, I would have stayed for one night in a London Hotel, had the treatment and gone home immediately after it, largely travelling by train. I regard it like having a tooth filled, you don't just pull it out because it might need further filling or attention at some time in the future and believe me, having had dental implants, that was much more painful.