I’ve not paid the final £1000 yet.
Honestly, I don’t really know what to do or how to handle it. It’s the first time I’ve ever paid a company to do a full job, and it’s been a thoroughly stressful and draining experience. I’m pretty broken and exhausted by it all right now.
Speak to him and advise that if he can't fix it to a
standard you would expect, you will get a "reasonable" quote from a professional tiler to redo it. However much it comes to, ask if he's prepared to knock it off the final payment. If a new quote comes in more than the £1000, you may have to suck up the remainder yourself, as it would have most likely cost you more to get a professional tiling job the first time round (but at least it wouldn't have needed doing twice).
If he goes for it, do your trust-a-wotsit review saying what you were happy with, what you weren't happy with but make a point of saying the guy may have bitten off more than he could chew but was reasonable in offering to contribute towards getting it fixed.