Hi LewisAirsofter
Let start with some basic facts:
Your 15
You have someone in your family over 18 (your dad) who may be interested in Airsoft as well (great stuff)
You want a black gun, cool no problem really
You want to use it at Skirmish sites, ok
Also I am a police officer
So basically you want to get into airsoft at the age of 15 years old and you want a black gun.
Firstly i would recommend that you and your dad go to a proper Airsoft site and rent the guns first time, see if you really like it and if its something you would like to do in the long run especially if your gonna drop a ton of cash into the sport, (trust me its always one more gun and accessory).
Ok so you have played and loved every second of it, so does your dad and you guys want to do it again, yay!
You have two options now, buy gun NOW! or buy gun LATER.
Buy gun NOW! (not recommended)
Ok so you cant wait, you want to get your hands on the very best Airsoft gun your budget can stretch to, well your dad will be stuck to buying two tone guns.
So he gets you a two one BB gun, depending on what model or type of gun you have a few options ranging from totally legal to questionable/grey area/are of "What if's"
You can:
Tape method: Buy black duck tape or fabric camo tape and tape up the parts that are two tone, this is totally legal as the tape is considered a temporary colour and so does not count.
Stripping the paint or spray painting over the two tone: I would not recommend this as it will make you gun look tacky and could be considered contrary to the VCRA, if you are set on doing this i would recommend you strip rather than paint over, i cant tell you how to strip the paint but there are previously mentioned ways.
Upgrade: Depending on the model,style and what's been painted as two tone you could probably replace those parts, i had a friend who had a two tone AEG with a bright green stock, pistol grip and non RIS handguard. The stock and pistol grip were replaced with cheap after market parts to make them black again, the front handguard was totally replaced from a non RIS handguard to a picatinny rail system, essentially his AEG was made totally not two tone.
Buy gun LATER! (recommended)
Your dad now has to play 2 further games (remember you have already played one above) over a period of more than 2 months, so don't bunch it all in there quick, play a few games spread over a 3 months period, ideally at the same site to ensure continuity.
So your dad gets a UKARA number and is now entitled to buy black guns, he and you go to a airsoft store be it in person or online, select a gun for you, he hands over the cash, UKARA is checked, and is fine, you walk out of the shop and he turns and says "here you go son, your gift", you will reply "thanks dad" and leave it at that. As soon as you give any service or money to him for the gun, he not you, will break the VCRA law as he has technically given you the gun for monetary gain.
Rather than pay your dad (which you shouldn't do) why not ask him to gift it to you now as a late/early birthday present so that he does not have to remember getting something for you later.
You can now attend any site now with your black, freely gifted gun and exchange plastic pleasantries with other airsofters.
Points to note:
You mention "I've been playing down at the woods near by with a mate for 2-3 months but we want to get into skirmishes and milsim", by this do you mean a public place or a registered Airsoft site? Because if this is a public place where any member of the public can waltz on into then be very careful, even if you say its somewhere that no one is ever likely to come across then think about it, i said any member of public, what are you? a Member of public so if your there then it's somewhere the public can go and you have therefore technically committed an offence of being in possession of an imitation firearm in a public place. If its at an Airsoft site then please carry on playing
As other have pointed out, never show your Airsoft gun in public, somethings are best left hidden from an already scared and jumpy public post Paris, Ivory Coast terrorist attacks etc keep the guns in bags or cases going from home to airsoft and back again. The general UK public cant tell the difference between a real gun and obvious toy gun let alone the very realistic Airsoft guns we play with, even police officers will have a hard time telling real guns from airsoft ones, i have even seen a registered airsoft players entire armoury seized by police because half my colleagues cant tell the difference between airsoft guns and real ones even after i asked why they spent the last 3 hours seizing, bagging and tagging every gun, magazine etc when i pointed out that he was legally allowed to own Airsoft guns, her reply was "but they are guns", I sighed and left.
As for gun you should get, someone mentioned the G&G Combat Machine range, very good and reliable guns they are and you should start on the M4 platform as it has a myriad of options to upgrade and accessories. Dont forget essentials like EYE PROTECTION, combat vests, clothing, gloves, hats, boots, extra mags and batteries.