Depends what spec it's got. Very basic manual, £9K. Fully loaded DSG, £10-£11K possibly.
Yeah but you think about the amount of them with 50k - 80k miles for a quite basic one looking 9K for them, at 19k miles it's still pretty much factory fresh.
They're over priced imo. A 19K old one is still a 10 year old car with 10 year old suspension bushes. It'll drive a bit tighter than a 100K old one, but it's far from factory fresh. This country is so out of date and outmoded way of thinking when it comes to cars. It's age that kills cars, not mileage.
I would rather have a 1 year old GTI that's done 100K miles, than a 10 year old GTI that's done 1K miles.
100k miles in a year living in Scotland working in England? 
I do understand what you mean though but age vs milage is never an easy comparison I think it's more about the person that has owned the car.
Age kills the parts not affected by moving eg seals, paint fade (if stored improperly) but Milage kills moving parts suspension etc. But I do think that's more with regular cars, the likes of performance cars and hot hatches (pretty much entry level performance) milage does matter more; turbo turbines wear, seals expand and contract etc.
Not all cars are owned by enthusiasts, and I've seen cars at 2k and 30k miles that you wouldn't take the gift of, then there's cars owned by enthusiasts that look new at 100k entirely depends on the owner and how they look after their car.
Edit;
Plus milage does help to judge driver imposed wear on components
Absolutely! I always buy on condition and ignore the age / mileage. Neither of those have particularly bothered me, otherwise I'd jump onto the 3+24 PCP bandwagon. I just like old VWs in good nick
The thing with age related wear/tear is rubber and brakes degrading. Brake hoses perish, tyres crack, brake pads rot, rubber bushes harden etc etc. And not only that, cars that aren't used just develop a foisty smell as no air flow gets through the interior on a regular basis.
Mileage as you say is a general yardstick for wear, but again, lots of short journeys kills off an engine far quicker than 1000s of stress free miles on the motorways. That's why I avoid "One lady owner" cars. I also don't like the handbag and key scratches on the roof and interior, or kerb rashed alloys. I know I'm generalizing a little there, but most women I know dump their handbag on the roof when closing / opening the door.
Anyway, if it was 19K and looked and smelled like it had just come out of the factory, I'd pay a premium for that. But if it's a tatty, neglected 19K, they can keep it
