My car 2008 audi a3 1.8t is pretty knackered at the mo. Main initial problem now is that I cant get it to start. I was revving the car on the drive to try find the source of a nasty noise under the bonnet when it just slowly died and cut out. Now I cant get it to start again. It just make a clicking/tapping sound. I have tried jumping it and bumping it but neither worked. Any idea what has knackered now.

Also I had it in yesterday morning for a diagnostics which came back with a cam sensor (g40)/ engine speed sensor (g25) incorrect correlation. This has been causing my car to struggle starting and be very lumpy when idle. Booked in for friday but now I cant get the bugger there! Help!