Does she wake if you unwrap her once she is asleep? Maybe you could try unwrapping her but then putting a sheet over her and tucking it in?
Yep, she normally wakes after about half an hour if unwrapped. But it has been a while since we've tried that, so will try again. And she also has a thin sheet over her, but she's so squirmy that that comes off, even with the swaddle on.

MummaSue - DD slept from 7.15pm to 4.15am... I woke up at 3am and checked on her ... so yeah she's sleeping so much better, but I'm waking up anyway to make sure she's ok LOL

I finally get this tummy sleeping business - about half my mum's group said "my baby won't sleep on their back" so their babies were put to sleep on their tummies from about 4 months old. One was even put to sleep on his tummy from 4 WEEKS old!!
I would have been WAY too scared to try that. In fact if DD hadn't started sleeping on her tummy by herself, I wouldn't put her on her tummy even now.