Yeah i thinks so...goodness i am pathetic

it's mainly because it's such a protracted process, you're there for ages. (3 nights, 4 days for me). you'll definitely need to work on your maths, some colleges asked quite a lot in the interview eg apparently jesus always has a numerical question. balliol didn't ask any though, apparently the head economics tutor isn't a bit fan of maths.
if you get below a certain score on the tsa then you will automatically be rejected before interview, i can't say any more than than re how important it is, since scores haven't been released (can't see correlation). i'd practice a lot for it if i were you, people say it's about how you think etc, can't be prepared for, didn't find this was my experience, i improved so so much (like by 15%) after doing a few papers. the same kinds of questions crop up each time. i should have some extra papers floating around the house, i could send them to you if you like? also for the essay, i found this blog really helpful
http://stumblingandmumbling.typepad.com/, actually used a concept i'd learnt about there in my essay

(availability heuristic). or something like that. it would be excellent if you could produce an essay similar to that, logical, concise, interesting ideas.