Thanks everyone. DS definitely doesn't want a garden, he would see it as a major hassle and never use it. He currently happily lives in one room that is smaller that this so I don't think it would quickly feel claustrophobic or anything to him - although he would definitely need to streamline his lego collection which is currently at our house!
He's a bit different from most people (including me!). He likes the idea of a studio because he can't see the need to have a separate bedroom/living room because he has always 'lived' in one room. I don't remember him ever sitting on the sofa at home and he'd happily have eaten all his meals in his room on his bed if he was allowed when he lived here. He doesn't have a sofa in his rented room either, just a bed.
Personally I think he needs a bed and sofa because I'd like somewhere proper to sit when I go round, I don't want to perch on his bed and I don't think it's great for him to be doing everything from bed! Not sure if I'm being controlling there or just normal and sensible.
I know most people wouldn't want to live in a small studio long term, but he probably will because he doesn't really want the things most people want like a partner, family, outdoor space, a house.
I don't think the 2 other flats for sale for £130,000 are in quite the same place as this one, they seem to be on London Rd which is a bigger busier road I think. That probably wouldn't bother DS though.