Thanks for the replies, ladies. Although I can feel the edge of the damn thing with an index finger, I just can't hook a finger onto the edge of it. The top of the vagina plus ring seems to flop away out of reach when I try. I tried bearing down while in a squatting position but to no avail. I even fell over on the second attempt!
I'll have another go, but perhaps I'll have to have it removed at the surgery when changeover time comes.
Apart from all that, it's giving good results.
Thanks again, JP x