Ray, I'm not here to argue with you, but you've contradicted yourself here.
You called them to cancel the service appointment because you'd found a cheaper quote (£50 cheaper). Going by what you've stated, you wouldn't have known that they'd offer to match the price - so how can you possibly say that you might have given them the business if they hadn't offered to match the quote!
They were damned from the moment you decided to get a second quote.
Will
I submitted post 16 above as clarification. Assume posts crossed.