Thankyou all for your helpful (and amusing replies). Had the interview on Monday, got to say it was certainly different from all other interviews I've been to in my life. 20 mins of questioning,which didnt seem to have any structure to it or didnt seem very pre-planned just very casual and on the spot,and then 10 mins of technical questioning from someone else. Now I'm on the long bastading wait to find out if I got the job.If only I were as confident about the whole interview as I am about the technical bit.