This event is happening on Sunday 28th March
As you can see from the list above, theres some seriously nice cars going. I've had a brief skim through the thread on Pistonheads and their plan is to do the run from 6am onwards, and then all go somewhere for breakfast. Not sure about the route they're using or the tunnels either yet - haven't read through the 17 pages of info!
Further details are here:
http://www.pistonheads.co.uk/gassing...nel Run &mid=0
edit/ when i opened this thread to start reading, only Crowmans first post was there 
that'll teach me to open threads, then go off an read Pistonheads before replying!