Advice, plumbing?

Originally Posted by bluefishman

You are right to be worried about somebody finishing the job, most will not touch it. I'm sure you find somebody to do it though

Aye we were, however the gas safe investigator spend over an hour checking the work and has said it is certifiable and that a registered gas fitter should certify it with no issues

Glad you got it sorted despite all the worry.
You can
Move on and hopefully the cowboy will get caught.