I love that site! It's a really good CQB site with a very good briefing in the café. You're in good hands.
The safe zone where you mill about with unloaded rifs and chat with the other chaps and chapesses is around the back of the place. Find the tank and head North. Look for the smokers hovering at the entrance to the wooden building and you're there. Ask them where the sign in place is. If they are not there, just look for the sign to your right. A very mellow chap called Sean IIRC will answer any questions that you have, and give you a waiver to sign.
If I go myself, I'll send you a PM. I was talking about going with the lad the other day. The games are well thought out and the gameplay is good. Ask a marshal if you need advice. There are a few ex-Royal Anglians who play as a team who go regularly. They are a very friendly bunch, as are most of the people I've met there over the years.
The games are short fast and furious. Flanking is king. In CQB shoot first and identify later.