Poo - viewers of a sensitive nature may find some scenes distressing

I'm not sure what the dictionary definition of "potty-trained" is, but assuming it's along the lines of "has control of bowel and bladder movements and can relieve oneself when and where one wants",  L is potty trained.

It's just not working out quite how I'd like.

We did it in June - we were staying in a house with a downstairs loo and no carpets so it seemed wise.  She was great.  We cracked the wees pretty much straightaway with the help of some haute couture Iggle Piggle pants, and the poos seemed fine too.  She's still in a nappy for her nap and at night so the fact that we occasionally had a poo in a nappy didn't seem to be a problem.

Only now it's the end of October, and we don't seem to have got any further.  It's not that she can't control it,  she's in 100% control (which I think maybe the driving force behind it), it's just that she does her poos where and when she'd like (in her nappy, five minutes after I've put her to bed) and not where and when I'd like (on the loo, at a time of her choosing).  Oh and yesterday she tried to clean herself up too....

I've resorted to the parenting books (not normally my preferred reading unless I want to feel more guilty than I already do), and they say helpful things like "it is important to find out the reason your child is doing this".  How do you do that with a 2 year old?  L is pretty articulate, but I don't think she knows why she's doing it, much less has the vocabulary, or self-awareness to put it into words.

We've had lots of conversations about it, so she knows that she's a big girl, and big girls use the loo and she knows that babies use a nappy, and she's not a baby, and that her friends use the loo; and she agrees and smiles and goes on her own merry way.  We even resorted to bribery:

Me: "L, what could I give you that would make you do a poo on the loo"
L: (thinks hard, for the most outlandish and exotic thing she can imagine) "a lollipop"
Me: (very relieved, having been slightly concerned at having to explain acquisition of a puppy to non-dog-loving husband) "well, as it so happens I have a lollipop downstairs, if you do a poo on the loo, you can have a lollipop"
L: "I don't want a lollipop".

Right.

I know, because I've learned this over the last 2 1/2 years, that this too will pass, and when she's 15 she won't still be in nappies, but I just can't see how. Presumably at some point she will just decide that she's ready, but oh, don't I wish she'd do so soon!