Went with installer as per yourselves, when we had problems with boiler it was difficult to contact yourselves as phones very busy and told to call back later. After boiler had broken down on the second occasion we were notified of the incorrect condenser pipe . By your engineer. We then notified installer who came out after several days , but we are still waiting for the outside pipes to be insulated and had been collecting water in a bucket in airing cupboard until there was no risk of frost to prevent damage to boiler . Have rang installer on at least three occasions re insulation but still waiting.