@GlazingNightmare
Hi everyone, he ended up coming round today (did I mention he's been really unreliable too?) and I spoke to him about the issues. He's getting certificates for us, but wasn't sure of timescales; he hasn't invoiced us for the 75% balance yet so I won't settle up until I have all the relevant paperwork.
He is adamant the windows are new, he says they've got a bit grubby but the holes were drilled because he mistakenly thought that's where we wanted the blind to go.
He improved the finish on a couple of the worst windows, and while it's not great, I can see that if I sand it a bit and paint, it will look okay.
I think this is honestly as good as it's going to get. Massive lessons learned 
OMG you should not have to sand and paint to make your windows look a little bit better. I can't believe he wasn't ashamed and fixed it all properly. Any good work man would be doing everything possible to rectify things and make good on a job you're not happy with.
Blinds do not attach to window frames, there's a bracket that attaches to the wall on each side and the blind is slotted into it. I've never seen a blind attached to a frame. I've blinds all over my house and not one is attached to the window frame.
You can't accept him leaving the window with the holes, every time you open your curtains you are going to see these holes and they are going to annoy you. How deep are the holes? Is there any possibility that they will result in damp and mildew?
All the other things you've listed is even worse than when I previously replied. There's so much more wrong.
This isn't a small issue, you have to look at these windows every day. My windows are 20 years old and they look better.
If you got a new kitchen or bathroom you wouldn't say you'll finish it off, or try to make it look a bit better.
What's your dh saying? If they've a good friendship they'll remain friends, tbh I would give a crap and I'd make sure to get it fixed.
If it were me, I'd get a window company out to do up an invoice of what needs to be done, give it to him and show him that these are not acceptable. I would not even get him to rectify this, he's obviously not a proper window fitter, which concerns me too, because looking at that, I'd wonder if they'd withstand bad weather, will you have draughts etc,, and then I'd get the other window company to do it properly and not pay your man.