Hi, James.
Welcome to the forum, mate.
I'm sorry that you're still suffering from incontinence two years after your prostatectomy. You're not alone, apparently about 5-7% of men can have long term incontinence.
I found this link by POPG UK (Pelvic, Obstetric and Gynaecological Physiotherapy) which details the problem and how it can be treated.
https://thepogp.co.uk/_userfiles/pages/files/rahman.pdf
I know there are posters who've suffered long term incontinence and some have had surgical intervention. Perhaps they'll post their personal experiences.
Good luck, mate. 👍