Ha Charmion, gnashers and gnawers are dreadful aren't they? We once had a cat called SimpsonSam who loved to chew woolly jumpers. I always drape thick knitted garments on the radiators to 'finish them off' before putting them away in a drawer, and while we were out he would tug on one sleeve, pull the garment to the floor and get busy. He once chewed away an entire sleeve!
It's funny, our study too is on the windward side of the house, and rather chilly (French doors,and not double-glazed) so three weeks ago we had a new lot installed by an excellent firm. Cost an arm and a leg, but now the room is hermetically sealed and very snug. In summer we can open wide these swanky new doors into the conservatory and enjoy the sun. (Oh please let it be soon!)