1. I recommend googling Surrey Airsot and see what turns up, but I know of one site, it's in Reading and set in a old shopping center, called "The Mall" it's meant to be pretty awesome.
2. If your own kit works, use that. Test it first. Make sure whatever site you visit, the weapons are within their FPS rules, if you can't test them yourself, you likely can find out their FPS by googling up the weapons or get them tested at the site.
3. 99% sites are walk-on, that said, like anything these days, if you become a member of the site, you normally get a discount for playing.
4. See whatever site rules you visit on if they allowed or not, but normally they are allowed, that said, if you use propane gas, everyone will hate you because that crap smells, no hiding from it, everyone can smell it.
5. Yes most of the time, people will play fair, but there are cheaters in all games. If you suspect someone cheating, shoot them more or tell the referee, but be mindful, due to equipment, adrenaline and the chaos of war, someone might not feel their "hits". It happens. But don't worry about it, most people play fair.
6. Most sites just play normal games but rules can be different everywhere. I don't think there is a 100% dedicated milsim site, since them games an take time to prepare.
Normal games are standard games you see in FPS games, deathmatch, search and destroy, CTF, hostage rescue, attack and defend and anything else with simple rules. You be told what the game is before you start and things will be explained.
My local site plays games like the above, sometimes they do something extra or change things up, nothing milsim, don't know what it's like at other sites, but most normal games, it's all fun and giggles and good sportsmenship mixed in with some serious play.
