Poor Workmanship in Joinery

Ale88WL

Hello, we just had independent joiners coming to our kitchen to fit a new worktop, plus wooden backsplash and install sink and gas hob.
At the first glance, the work seemed to be done properly. However, after a closer inspection, on the same day the work was done, we noticed:

1) that the wooden backsplash had been badly cut and is not straight, leaving gaps of different size along the wall. 
2) that the worktop edges had been poorly fitted.
3) that the sink has been just left in the fitted hole, but not attached to the worktop
4) they did not use any of the materials we wanted them to use as sealant and bolting joints.
5) The most important/dangerous: while we were cleaning the kitchen we noticed an intense smell of gas. I immediately turned the central gas tap off and called British Gas. Upon arrival, the engineer said there was a massive leak and that the gas supply pipe in th kitchen had been bent multiple times, so there were multiple places where gas was coming off. 

Importantly, we learned from him that no one who is not a qualified gas engineer should touch gas pipes and that it is a criminal offence in England (a fact that was confirmed by the engineer we had visiting the next day to change the gas pipe and check everything was fine). 

Meanwhile, we have been contacted by the person who did the job to arrange payment. We highlighted all these faults and that we would not pay in full, especially since they left us in hazard. The person replied that he would come to rectify the issue and then get the full payment, but honestly I don't want them to touch anything else after what happened. Besides, the issue of the backsplash cannot be rectified as I don't have any more of the material (and don't want to order and pay for it again to eventually get it once again ruined). So I offered them to pay for the  part of the job that was done decently (the fitting of the worktop), but that I would not pay for the rest (especially since I will have to pay somebody else later to fix the issues).

Any suggestion/recommendations?

Aylesbury_Duck

That sounds like an appropriate way forward.

Get a registered gas fitter to come and correct the gas problem ASAP.

tacpot12

If your offer isn't accepted or they threaten legl action, check to see if you have Legal Expenses cover as part of your Home Insurance. If you do, you can call the Legal Helpline for advice. If they know that you wll have legal representation on court, they should be more likely to accept that they have got what they can out of you.