Bike - £60-100
Sub fusc - gown etc £45?ish? plus shirt/suit/trousers... who knows.
Food - £50 per week (you could easily, easily live off £20!)
Transport from the airport... depends on the method (bus/train/taxi)
Nights out - I have good nights out where I've spent <£10 incl. clubbing, but guess at 3 x £20 nights out in freshers week