It's early next year so there's time but I have no ideas whatsoever.
He never asks for anything other than books. He doesn't want to learn to drive for environmental reasons and says he will always live in cities so no need, so nothing car-related. He isn't very materialistic and doesn't wear a watch and has no interest in high-end items along those lines - would lose/break or just not ever use them. He has all the tech he needs and isn't interested in it as long as it works.
He does love two sports and rarely gets to games/matches so I did consider something like a season ticket, but one I don't even know if I'd be successful/could afford it, and anyway, he'll be at uni so won't be around for most of the year to attend games. Plus it's temporary and I feel it should be something that lasts for an 18th. I did think about trying to get tickets for a few games throughout the year of his 18th, but, again, temporary, and one team I have no idea how you even get the tickets - Premier league. I've looked before and it seems they are never available?
He likes travel and experiences/shows/theatre but, despite having a large friendship group and busy social life he has no best friend nor, at the moment anyway, a b/gf (he never has had) and so wouldn't know who could accompany him. I could but don't want his 18th gift to come across as being partly for me! And that would also be temporary anyway.
Any thoughts, suggestions or details of what others did that was well-received by a similar-sounding 18yo would be massively appreciated!