If you haven't already then you may want to check out some of the guides on here buddy:
http://www.airsoft-forums.co.uk/index.php/topic/12854-new-player-guides-info/
And this to help you find a gun:
http://www.airsoft-forums.co.uk/index.php/topic/17294-ians-guide-to-noobism-on-a-tight-budget/
Also, if you can visit you local site a few times before spending loads of money.
If you haven't already try to read up on the law.
Also:
From what I've read on here, people advise not to buy from websites that have the phrase :"Bbguns" in there name but that's upto you
There are quite a few good sites such as:
-ZeroOneAirsoft - They 2-tone for free
-ProAirsoftSupplies - Good all round
-Taiwangun - Polish company, but the things are cheap
LandWarriorAirsoft - Have lots of brands you struggle to find in the UK
-PatrolBase - Generally a nice website for gear, gun stock isn't as good
Hope this helps buddy!
And can someone correct me if I've done something I shouldn't have or have got something wrong!