I suspect the light was illuminated hence the fail. Then they likely cleared the codes and/or did a battery reset. It may well be the light will come on again depending on what the issue is that caused it to light in the first place. Could be a myriad of things, needs a code reader when it happens again. Does it have an aftermarket exhaust?
Yes I think you are correct. I am now discounting the blue car unfortunately as there are a number of question marks arrising. Firstly it has had the o/s/f lower wishbone has been replaced, but the n/s/f has not and on the MOT advisory the n/s lower balljoint has some play. Also, there is only one key, the second cannot be found. At that point I am out.
So, Optimum cars in York has a 55 plate with 65k miles, full history, all keys, just serviced and fresh mot with no advisories. Top end of the budget for a 4200 but it comes with 12month warranty so, I’m in again....subjrct to the front subframe being solid and clutch being good.