How do I relight the pilot light in Potterton Prima Boiler?

My Potterton Prima 60L or 60C (I have no manual and can't read the engineer's handwriting) has stopped working. Its New Year's eve and Im stuck in the house with no plumber available and its freezing! Can anyone help?
I live in a rented property and there is no manual for the boiler. I turned the central heating on 2 hours ago but the radiators never came on and when I checked, the pilot light is not on, nor does it light when I turn the heating on. It makes a small clicking noise but no flame appears and I can't seem to find a manual spark button. Any ideas?