Kwacky: I never filter. I sit patiently behind the traffic and wait my turn.
Are you serious? I'll filter through nearly stationary traffic or slow moving traffic but it depends on conditions. In the event of an accident I think the best you get is 50 / 50 in terms of fault.
My instructor turned up later for my mock DAS test when I was taking it a few years back because he had been a witness to an accident on the A14. We went out for a mock test and I thought everything was good for getting to the test on time. He then turned to me and said if I wanted to get there on time I should follow him closely and keep a good eye to the left for any traffic coming at us - as he gave me an impromtu lesson in filtering through the rush hour in Cambridge 
If nothing else it stopped me from thinking about the test too much!
Sorry to hear about the mate Bratty. A knackered gear lever and broken chain isn't too bad to fix for Thursday. If he's still taking the test I wish him the best of luck. The best thing to do after experiences like that is to get back out there as soon as possible taking any lessons learnt with you.