I'm meeting them tomorrow and plan on taking some photo's to remind them how it was originally, what would happen if they attempt the repairs, costing themselves money, yet the repairs aren't up to the original condition? Or do I need to sit down with them and detail exactly what's required, in other words, how much say do I have in the repairs they carry out? for example what if they were to use gloss paint to repair a matt painted wall?
If they did that, then it would comprise damage, as you'd have to repaint the wall to put it right.
You can't stop them doing stupid things like this, but you can remind them that they are liable for any damage caused by them, and bodged repairs count as damage.