Dangerously fitted woodburner

[ohbuggerhelp]

I hope someone can help!
We had a woodburner fitted last year by a chap . We went to have it swept last week and it is dangerous!
basically, wrong position, no register plate, no proper chimney cowl and much worse, liner is 3 m too short and resting on the inside of the chimney in a 400 yr old timber framed house!

And the guy isn't HETAS registered despite telling us he was!

Anyway, a proper fitter is going to put it all right but at a cost of over a thousand pounds. We are going to ask the original fitter to repay that money and we have photos and a statement from the new fitter.
Legally, where do we stand?

Thank you so much x.

What proof do you have that he told you he was HETAS registered? We have just had a woodburner fitted and the chap showed us all his certificates. We also had a HETAS form at the end (one for us, one for him and one we sent back to HETAS) showing that the work was completed as per building regs in case it ever comes up when we sell. I am guessing that you would need to prove that he knowingly misled you?