Went to view a flat in Crawley today (after a slight detour via East Grinstead when I got on the wrong train), but it was a bit small. So, I think I'm now going to look at more expensive places. I'm also favouring Croydon over Crawley - I don't think one has better value for money than the other, but Croydon doesn't seem to have many of the small/cheap flats that Crawley offers. Also, a season ticket between Crawley/London is £100/month more expensive than one between Croydon/London, so I think I'd rather spend the extra money on mortgage payments instead. (Mind you, that situation reverses itself if I wind up working/studying in Brighton.) Thanks to all for the previous advice; I'm now widening my search for mortgage providers, and looking at the Halifax in particular. Admittedly, this is partly because of the tacky adverts on TV, which I guess served their purpose by sticking in my mind.
Meanwhile, things are a bit slow on the university front (still no sign of my student card, therefore no library access), but I'll meet my supervisor in a couple of weeks to plan out my project in more detail.