I have still got the standard pirellis on at the mo but the fronts are wearing out. Just wondered if I would be best swapping front and rear (rears like new) then buying a full new set (poss some toyos), or buy a couple of new pirellis?

I had my rears swapped with my fronts when my wheels were done & I wasnt entirely happy because it meant I needed 4 new tyres in one go, which meant mucho money (I just stuck with the Pierellis)! Just depends if you want to squeeze everything you've got out of the Pirellis and replace all 4 in one go or have a mix n match tyre set

Bad idea.

That means your rears will not have as much grip then. It is always said the most worn tyres should be on the front.
I know this from experience as well. Mk 4 Fez, worn tyres put on the back, wet road, slight bend. Before you could blink, I was looking at where I just came from.

Buy new tyres, its a better idea.