Thank you everyone for your really useful comments. Personally, I am leaning much more towards radiotherapy as I am still quite young and the surgeon told me that in my case ED would be a big deal and ED meds will not help a great deal. I also don't really want to go under the knife and have the long recovery period. Plus there is the climacturia. I am also at fairly high risk of microscopic metastatic disease spread and the radiation oncologist tells me that RT takes wider margins and reduces my chances of spread where as 30% of patients that have undergone RP end up with some RT within a few years of surgery.
Concerned about the effect this will all have on my rectum as a receptive partner in anal sex, but the stats are quit good and everyone is different, so no real way of knowing. Erections should also be better (initially) and although have a chance of dysfunction 5-10 years after RT, ED meds can help.
If any bottoms out there had RT as first line treatment, I'd really be keen to hear from you. I am so happy to hear that many of you are enjoying receptive sex post RP - that's amazing!
Do feel free to message me privately but as a new member, I cannot reply for a bit, it seems!
Take care and greetings from Christchurch, New Zealand x