The scratching has got to a point where I've considered glossing our beautiful wooden door frames in an attempt to get him to stop scratching. Then I had an idea. I got 4 Tesco own brand doormats and some upholstery pins. Cut the mats into strips and tacked the strips to the door frames. He can scratch as much as he likes as the mats have rubber backing so should last quite a long time and he won;t get shouted at for doing what's natural for him. We've kept his claws short and so far the scratching has subsided. I think the tesco-doormat-tacking-mission was a success.
Yes, OK, this is only really suitable for people who don't mind their doors looking like they have bumpers but, I'd rather spend £5 and not have scratched door frames than have to spend hundreds getting all of the woodwork re-done. Job done!