I was somewhat intrigued by the use of the term mainland, but it certainly has some debate behind it: https://english.stackexchange.com/questions/3652/how-to-refe...
Yes second hand cars in the UK are cheaper, factors being that there has been a consumer rise for a while, seeing more second hand cars. This with the island effect makes for dispersal of those second hand goods more curtailed and for example you may be able to get cheaper cars in Germany second hand if the geography curtailed those easily shifting to nearby countries who have had less of a consumer drive.
Which is why my friend in Bulgaria will buy a second hand car in the UK, drive it back, sell it for twice what he paid for it. Then in Bulgaria Walnut wood is about 1/5th of the price of what it demands in the UK. But most opportunities in life are going the extra mile.
Yes UK is still technically an EU member during the transition period. How exporting/importing of cars pans out, well as long as the we don't end up with trade loop-holes - then I'll be happy and by that. Say EU has import tax of 30% on UK cars, new or second hand. Yet no such taxes for imports from say canada. Then the UK has no tax import on cars from UK to canada, so would be possible to export to Europe, via Canada to skirt such import taxes. That kinda thing worries me as environmentally, not good. But could happen.
All I do know though is that the current trade negotiations seem like a Monty Python playbook:- https://www.youtube.com/watch?v=CK0cUv3ba-o
something to do with steering wheel being on wrong site making them useless to all of EU other than for parts.
I believe it stems from a tradition of not disposing of things, and instead selling them on (via "car boot" sales) or handing them down. I believe (and this is pure conjecture) that it's a recent thing for brits to dispose of things with such frivolity, and this is somewhat echoed in the car-boot sales of late being chock-full of brand new mostly chinese cheap crap.
And maybe if you have an overabundance of second-hand goods then maybe the price goes down as all of the friction to sell even things considered "tat" are gone.
And most of the things we would consider "tat" are not "tat" to everyone else, for instance, I bought my first computers for 5gbp from a boot-sale, for such a token amount of money it is likely a person would not have sold it another way. Thus, I get a cheaper computer than I would have had to pay otherwise.
Our used cars go for peanuts compared to used cars in the mainland for example.
I am often trawling the UK ebay for tech stuff because it's so much cheaper than Blocket (a craigslist-like) here in Sweden.
PS: very very pedantically and technically, UK isn't an EU member any longer. Although there is some limbo period.