I chose Impra Gas as they gave a guaranty that they would price match any quote, this is also stated in there literature. Unfortunately I am still waiting after three months with no satisfaction in the wings.
I also had problems with the installation, they said it would take one day the first engineer although quite good he didn't have enough time as he had to travel home. I was told another engineer would come, this happened two days latter than promised, but I had to complete the electrical part of the installation.
They took a water sample which they said I would get the results (still waiting)
Their service from the office is abysmal and it is no wonder Lord Sugar drooped them. It now looks like I will have to take legal advice to get this sorted