busymum wrote: Is the issue an immature system or heavy sleeping or something medical, do you think?

In Michaela's case I think it's probably an immature system and heavy sleeping.  We actually had to "actively encourage" her to night time toilet train, if it'd been up to her she'd still be in nappies at night, and it was only late last year that we made her start wearing knickers to bed.  I'm just taking each day as it comes.  At the moment I don't mind taking her to the toilet in her sleep but if it persists then I'll speak to her doctor about it.

Totally guessing here, but could she be sleep-crying (for want of a better term)?  Her actions sound like a sleep walker - I remember my sister coming out into the lounge and *watching* TV when she was little, but she just stared without blinking, muttered "mmm" when asked questions and didn't believe us the next day when we talked about what happened the previous night as she had no recollection of it.

At least she cries, so you can help her with toileting and avoid changing wet sheets . 

Michaela is only 5 weeks away from starting school and I still toilet her every night at 9:30pm.  She doesn't wake for it at all.  I actually have an alarm set because if I don't remember I'll end up having to change her sheets.