Report them to gas safe. Tell gas safe you feel the standard of work falls well below that of a registered engineer and tell them you expect them to send out and inspector to look at the work. I don’t suppose you know what boiler it is do you?
It is a Vailliant boiler, some years old, and it was a Vailliant boiler suited man/men in Vailliant Vans that came to do the "work" i will look into the gas safe complaint procedure, but my main aim now is to get the house heated and a boiler that works, fortunatly the neighbour can take the knock financially , and in fear of repeating myself its the moral side of this that is simply wrong. If persuing a complaint via gas safe was to delay proceedings of a new boiler, then i wouldnt want that , even more so if the procedure could possibly mean Valliant fitting a new Villiant boiler, then just for the sake of being stubbon, i wouldnt want a Valliant boiler either . i believe my best/ easiest course or redress would be to publicise and promote my neighbours story and to buy a different branded boiler to replace the (aged) one she has currently
My advice is get her an ideal logic. She will get a long warranty. So no need for stupid home serve type cover and if she was unlucky enough to have an issue, ideal are a great company to deal with. As a side note. The only time I’ve seen a Vailant that was beyond economical repair was when the main heat exchanger was blocked solid with sludge. And that will kill any boiler.