Can anyone please suggest how to remove the old ITV sticker from my windscreen without damaging the screen

Scrape with one of those scrapers used to clean ceramic hobs. Any remaining glue can then be removed with "non sticky, sticky stuff remover"!

... alternatively, try a blow torch

some come off if sprayed with a fine mist of water then a sheet of plastic cooking film smoothed down over it for about 5 - 10 minutes.

Lift a corner and see if it will peel back, it works on some, ymmv

Hope it helps

Thanks both.

Will try the water and cling film method first. Not too sure about the blow torch

Leave car in the sun for a while or use a hairdryer to soften the sticker then scrape of with a razor blade or putty knife. The remaining residue can be cleaned off with normal window cleaner or rubbing alcohol.

There's a paint brush cleaning solution, comes in a red tin and contains toluene.

So far I haven't found anything it won't remove.

failing all else,i find a sledgehammer works
thats what i will do to my car as the timing belt buggered up on the motorway,100e for grua and a useless car
aka john cleese

Bummer. Really sorry to hear that.