A had another session last night and I think I made a little headway.
Thanks to those who have commented on my blog entries so far, I have done my best to act on what you have suggested. I have switched on to the fact that I have been trying to rush into all this too fast and I have been going at my previous sessions at a pace to try and 'force some progress out of it'. This, of course, is not right. So last night I changed tack and took things nice and slow.
Previously I had been just using my sphincter muscles to move the aneros, doing so with rapid contractions, almost hammering away at my prostate to try and get it to do something. This time, I tried not to use my sphincter at all and just concentrate on PC. Tensing it and holding it there for as long as I could in order to practice. After about an hour I started to feel the beginnings of some very pleasant feelings that would start off at my prostate but would then feel stronger down the backs of my thighs. Though I tried to focus on what I was feeling I soon lost it and decided to call it a night.
I will continue with PC muscle practice next time round and replicate the slow pace I did last time. Just to think, I never even acknowledged that muscle until joining this community!