heateam actually offer a very good price and service in that they are experts on their own products and the price quoted includes all spare parts and labour, when you think that a new fan could cost 250 fitted, a new circuit board 250 then this is very good value.
when you say the flame failed due to low water pressure are you actually referring to the pressure of the mains cold water entering the boiler when you are trying to run hot water or the water pressure within the boiler for the heating (as shown by the pressure guage on the boiler)
if your mains water pressure is too low to operate the boiler then you could be in trouble as heatteam are only going to repair the appliance under warranty if it has been installed correctly I.e. correct pipe sizing, water pressure, gas pressures etc. And can i tell you that i was chatting with a baxi engineer recently and 80% of all warranty call outs are due to the appliance being fitted incorrectly so they then have to charge the poor householder for any work undertaken.