Am I right in thinking she's about 14-15 weeks old?

If so, any change at this age can bring about some temporary stress with unexpected results and the other pup going could have caused that.

Have you changed the bedding since this started (rather than just washing it, trying something new in there)? It may help break the cycle that has started to develop. Also any toys/comforters you may have in there too. Make it as fresh a start as possible to see if it helps.

Would it be worth feeding her later??

Ollie did this same thing a bit ago, was fine no messing at all over night for a couple of months, had me thinking he was a breeze, then.... he learned how to aim and was leaving me a puddle outside the door, I started getting up in the middle of sleep time to let him out to pee and it stopped, and for the past week back on no toilet break in the middle of the night and no messes. Think he just got a bit confused!

take a close look at feed schedual and the durations of the dogs stay in the create, my pack will mess,when iv changed, something as simple as ,getting them out to early,stuff like that,sounds like there is change at this time,it will stop, they dont like it either,hang in there..

She's just over 19 weeks now.

Anyway, thought I would update this, Rave has now been clean for the last 3 nights, fingers crossed that it continues.