Update:
As I suspected, the fact that I contacted him for a date was a screaming flag that he wasn't interested. So next time I won't do that, but it was worth testing this out. So, we watched a movie and I had to stop him and ask him directly what he was thinking because he simply hadn't told me. Basically, he said he doesn't feel a spark with me, that we're at different stages in life etc. I'm about to graduate, he has a job. He thinks I need to get a sense of what I like doing in life - he thinks I haven't found my niche yet. I said that was fine (how can anyone be sure straight away?) but that he should have told me sooner. I reacted quite well. I did not get visibly upset or anything like that, no tears in my eyes.
He's been single for 4 years now. His first (and only serious) relationship lasted 5 and a half years and they split up when she moved down under. They are still good friends. He said he knows the 'one' when he finds her but until then he wants to meet new people and have a good time. I guess he goes for that instant 'spark', you know she's going to be the girl you marry kind of thing. He said he likes girls who are more outgoing than me. He goes on hundreds of mile cycle rides and used to play sport professionally. He says he wants a girl who challenges him. Funny thought is that I probably was challenging him because I was that different haha, only he didn't realise.
The conversation was so bloody awkward, lots of bad silences etc. I would have preferred if he had said no to the date or not replied. I would have been able to take it.
Thing is that I suspect he only wanted sex to begin with in spite of what he says. He says he thought about it after we had sex and realised that there was no spark. However, when I think back to our meeting (and I know I took the bait), he never asked me many questions about myself at all. He seemed pretty half-hearted and he did push for sex quicker than I'm used to. In spite of what he says, I'm not an idiot, and I wonder if sex was what he wanted all along. But by the sounds of it, he doesn't seem to know what he wants. Confusing. Would appreciate it if some TSR men could translate some of what he said so I can make better sense of it.
We both passed on our best wishes (extremely awkwardly) but I left something at his house (whoops) so now I will have to encounter him again... oh dear.