2 year old won't wear nappies

[disniq]

I know, I know, this sounds like the opposite of a problem.

dd started pt 2 weeks ago, and she's doing fantastic. She very rarely has an accident in the day at home. She started throwing one when I tried to put a nappy on for trips out of the house - mostly shopping - so I'm trying to keep her knickers on more outside too when i can.

My problem is at night. She'll let me put the nappy on and put her to bed, but between her bed time and mine she removes her pjs and the nappy and is wetting in her sleep.

I've tried leaving the potty in her room, and she uses it fine in the morning, but isn't waking up to go through the night. From what I remember with ds's pt, this is just a matter of time. But I cannot change sheets every single day without losing my marbles so, any tips in the meantime?

Mother care sell terry towling knickers. I think they are like pull ups but are made of material so actually look and feel like knickers only slightly thicker. Maybe this would work.
I have a different problem- my ds 2 has just worked out how to take his nappy off (but is no where near ready to toilet train) and keeps weeing on the floor!