Send your local perm organiser (ours is Danial and I think he covers that part of the world too an event entry form (
http://www.aukweb.net/cal/entform.pdf), with the date you intend to ride and teh few other basic details reqd, you need to give it a name, but I don't think there are any hard and fast rules. Print the form, on the back write/print the controls you intend to use (place & cumulative distance). Put in an envelop with an SAE and the organisers current entry fee (best to confirm this). A card will then be sent to you.
Do the ride.
Post card with another SAE.
I tend to bulk-buy the cards. I also tend to provide Autoroute tracks for all of my entries, to make life easier for the organiser. The other advantage to having a pile of cards on hand is that you can do most of the above electronically, allowing for last minute entries, for example on the rare ocassions when we get nice weather.
Anyway, that's how it works for me. Best of luck, I'm afraid I won't make it this time as the rest of the month is looking full with other things and I've seen enough of England for a while...
AC