It's also a home office so whatever happens, we will have to gut the room for 2 days when it is re-done.
Is this our responsibility? Should we just pay all over again? How should we handle this?
Sorry it's a long one but any advice or opinions either way would be appreciated!
Likely not his fault, sometimes jobs - despite your best, do go wrong. I would expect him to do it again, but only charge his minimum for it - a no profit job.