That site is my local and it's an under 18s day only on 26th, the sunday game is at the site in dunstable. There is no site pyros only rule, last game some chaps asked about MK5s they had brought and were told they were fine. Most BFGs are fine too, although I believe the louder ones are banned(don't know much about pyro)
The other restrictions are no CO2 guns and I'm pretty sure under 18s are not allowed to use sniper rifles.
The two lane end(just outside high wycombe) games this month are this sunday and a week thursday.