Thank you for your kind replies.
The boys have grown up a little bit now and only occasionally (about once a day), do they climb the curtains or tear at the wallpaper.
They then get shut out of the lounge until they have calmed down.
OH only finished decorating the lounge this summer and we bought quite expensive curtains. The wallpaper is Beadboard Walldoctor as our walls are not very smooth. We have just bought another two rolls to replace the bad areas in due course. We will also paint over it eventually as we have noticed that the cats never claw the textured wallpaper in the dining room and that has emulsion paint on top.
We paid over £800 for the curtains as I thought they would see us out! The only thing I can do is try to thread any loose strands back into the curtains.
Winston has just come into the room to see me. He said hello in cat talk and came onto my lap for a cuddle and kiss, pushing his head under my chin. William is also here now and purring loudly. He wants to be fussed as well.
Despite the damage done, I am so pleased that we have them.