Just had some success!!
DD and I just spent 1 hour in her room, sorting through her desk. When we moved her into her new room I -naively- thought she would want to go through her desk/drawers/books but no, she just left everything in piles 
So as today is the first day of the hols and my DCs have been exhausted I decided today we would do absolutely nothing. Stay at home and just relax. I felt a bit mean at first asking my DD if she'd like to put her things away on her first day of freedom, but she agreed!
I gave her a bag for rubbish/recycling a chazzer box and a folder for special drawings/stories she wanted to keep.
She went through both drawers and the open compartment and actually binned things and donated things, I couldn't believe it!!
I went through her clothes drawers at the same time and pulled out a couple of chazzer bags full, her school socks (1carrier bag full) and put her out of season clothes away - result !!!!
She can now use her desk 
Also Fuzzpig mentioned up thread about not doing a "big" shop for a week. I've been doing the same thing this week. It's brilliant. We had lots if food left over from a party at the weekend, so we've used that up, the fridge/freezer has room !! It's so nice to open the freezer and see space -complete saddo-
Now I have to make pizza dough for a garlic pizza bread, my dough has been useless over the last couple of weeks. Anyone know if the heat causes bread flour to not work? If this one doesn't work I'll have to de-clutter the flour and replace with fresh 