I had my old back boiler system upgraded to a combi boiler by VHS. I really can't praise them enough, the pre installation survey was carried out very professionally, with all my questions and concerns being dealt with satisfactorily. Prior to installation, the communication was first class, I knew exactly what was happening at all times. The installation was a fair sized job, which I was apprehensive about, but it went very smoothly, and everything was cleaned up afterwards by two really lovely men, and all I had to do was put the carpet back down. I would be happy to recommend this company to anyone.