I had a viessman 29kw combi boiler installed by David Harris..these guys was very professional and knowledgeable about the whole process..the supplier supplied the wrong size boiler.. David told head office straight away.. resupplied straight away..but did not delay the job.. work was done very efficiently..and sooner than estimated. I would recommend heatable to everyone. Even a monthly payment options is really good..and a choose and book service..fully installed within 5 days,which is really great at winter time..other companies told me minimum 3 weeks at winter.I was really surprised at how great an online company would be. Will always be using them for the future.. thanks heatable