Just wanted to update everyone as I've seen a client who had it a few times and he's managed to completely cure himself using a fleshlight sex toy, gradually, over time. I know some of you mentioned partners with it so thought I'd share!
He said it took a while (not sure how long) but with gradual use and a LOT of lube he's now able to have full penetrative sex in which the foreskin goes right back and, even though there was an issue with sensitivity for a while, he's basically able to have a normal sex life now. I can really see the change in his confidence now which is why I decided to share for those of you with partners. Seems the key is to be able to solve it in their own time with a sex toy, no pressure, rather than hoping regular sex sorts it out etc.