Car appreciation... the aesthetics, the engineering, etc

I think I would probably prioritise a decent MOT history (i.e. ideally first time passes every year, not many advisories)

Would you prioritise number of owners over milage?

What everyone else said, but on your specific question....

Probably milage over owners. However, look at the timings. E.g. A first owner for a very short period of time could well be some sort of corporate entity. Likewise on say a 10yr car an owner for the first 2-3yrs will probably be someone on finance selling it, possibly even to themselves, so 2 owners would be = to 1 owner imo.

Hopefully in Reading you can find something that's done more motorway miles. Although I your budget and shortest, probably not.

Good luck.

Read up on how to buy a car. Best short advise.....

MIleage and number of owners TBH pretty irrelevant on a car over 8 years old IMO

Current condition is everything.

Buy private, literally no point in buying anything from a dealer under about £10k unless you need access to one of their (not great) finance packages. Every single person I've helped with buying cars the last ten years who have just defaulted to buying a random car from a dealer in the sub £10k bracket has had issues that have not been resolved, or they've been so british about it that they cannot pluck up the courage to go and take vehicle and its issues back to the dealer. You can also meet the original owner and not be buying blind.

Honda Jazz, Fiesta, I20, mazda 2 or 3. All with the basic or mid range petrol and a manual gearbox. Citroen C3 C4 with the basic petrol are OK, avoid the 1.6 diesel, a chocolate turd of an engine.

Avoid corsa/astra with 1.0 1.2 and 1.4 petrol, they all go boom
Avoid diesels that age, too many issues unless you really know what to look for.
Avoid yaris and I10 as they've all been flogged by delivery drivers unless you manage to find a random decent one.

Take a mate. And never buy the first car you see. If your desperate for a particular model, be sure to look at and drive at least two so you can get an even basic feel for why they both feel different to each other.

If your not a smoker, don't buy a smokers car, it is impossible to remove the pollution from it, its not just a smell, it actively degrades interior plastics, rubbers and materials and gives off carcinogens.