Okay, fair point. I can't comment on how different institutions weight the various course components. At my uni, the dissertation is worth a meagre 15% of the total degree, so quite realistic to hammer the dissertation but get a 2:1 overall. This fate is quite possible for me. I went the extra mile on the dissertation to make it a clear first but in doing so severely compromised my revision time for my finals next week. That said, I enter the exams with a guaranteed minimium 2:1 which is all I need to take up my PhD position in September. To that end, job done. However, I'd like to get a first for me though.