Hi John,
Two things that helped me, when I suffered from post RT incontinence were:
Tamsulosin, in all I was on it for over a year after RT, I think it works by making sure you do properly empty your bladder when you have a pee, certainly I had a good strong jet with it. My Consultant had told me that I would be on Tamsulosin for life, however after about a year I found I could do with out it.
Radiation Cystitis, I found Cranberries the best cure for this, not the Cranberry juice drinks they sell in supermarkets because when you look on the list of ingredients you find they are basically sugar and water with a few cranberries for flavour.
You want to get the actual berries, the supermarkets are full of them at the moment for Christmas dinners, boil them up for about ten minutes with a little water, and you will get cranberry stew, a bowl of that every day soon sorted my cystitis.
:)
Dave