[Closed] Help, G3 plumber needed! Ashton, Manchester

Long post, but bare with me...

I need an installation checking and signing off.

Ok, so here's the deal. I do general building and renovation work, kitchens, bathrooms, all that stuff....
I've done a couple of unvented installs recently with a plumber I know through a mutual friend, so I know what I'm doing, just haven't done the 1 day course.
Anyway, this job is a recommendation from the last. Plumber was supposed to meet me at the customers house and we'd do it together. I'm doing other jobs there also, new loft hatch and boarding out, new shower valve.
He was to get on with it and I would do all the piping and joinery as it was being moved from the airing cupboard to the loft.
Anyway, he didn't turn up and phoned to say he was stuck and just get on with it and he'd be there.
So, I shifted the old cylinder and cold header, re-piped it all, made a new ply base for the new cylinder as the original in the loft was chipboard! Still not there, said it would probably be morning now.
Apologised to customer about leaving with no hot water and got the heating back on for them at least.
Next day, he's still on his job, but will be there in a few hours. "Crack on and I'll be there soon". Had the tank fitted by lunchtime and tested everything was working and water tight. All ok, relief valves ok, expansion vessel, waste etc Sparky rewired it for me that morning too.
Still not turned up, called him, said was STILL stuck, but would call round to sign it off.
Not heard from him until today, he said he can't now sign it off as he didn't install it! Fair enough if I just called him up out the yellow pages, but in this case, out of order I think!
Turns out, he is G3 certified, but can't register it himself as he isn't personally registered. He was doing it through his mate who he works for. He's found out and basically said no, which again, is fair enough I suppose.

Now I'm left with an unvented cylinder that has not been properly checked or registered and a customer who is not exactly pleased. I know the customer fairly well and have done loads of work for him before, however I have explained the situation fully to him with regard to safety issues etc. He's OK for now, but obviously wants it sorting ASAP!

Installation is complete and has been operational for a week now.

It's a 250l Range Tribune, installed in a loft. All pipework, wiring and valves are easily accessible.

It's on a Y plan, pump, 3 port and new 2 port are in there original positions, in the old airing cupboard. The cylinder and expansion vessel are in the loft, just above.

Access is easy as a ladder/hatch has been fitted and there is also light up there too.

All in all, an easy inspection/quick test, fingers crossed...

Is there anyone around who can help, or recommend anyone??????

House is located immediately outside Ashton town center and is easy to find.

Many thanks