Having had time to reflect, it did strike me that it could be some kind of pathological inability to accept being wrong.
The initial conversation was fine, until he said he'd fit a universal rubber valve, and I said that there was a sensor in there. Although it was a perfectly acceptable misunderstanding at that point as not all cars have TPMS, instead of saying "oh yeah, d'oh!", perhaps in his mind he was already committed to the rubber valve being correct, and so he just kept on digging to the point of being offensive, before finally flouncing off when he ran out of ideas.
Anyway, it doesn't really matter. The main thing I've learned is that Google reviews are a crock o' shite and not to be trusted
