Left my 96 year old mother without heating after fitting a part , with the excuse it isn’t covered by the insurance. Left the house in a mess and the insulation in the loft tossed to one side so it doesn’t do it’s job. Header tank lid left off as was the insulation. I felt they were glad to leave , as a hoped for short job took longer than expected and they couldn’t get it going. Not a very good experience but they did offer me this little gem of advice “ why don’t you go to an independent engineer, they will be a lot cheaper” this is what I’ve done , they come Thursday.