Thanks everyone. Didn't realise the rental weapons were so good maybe I'll rent one next time I go. I'm still unsure why I would buy a cheap £200 weapon if the ones you can rent are better than that?
Also what magazine size is good to have. Is 470 rounds enough? I have seen 2300 round mags for assault rifles but that seems a bit extravagant.
Quick update. I have ben searching through different website and really like the Tokyo Marui Pro Line M4 rifles. I have narrowed it down to two:
Am I right in saying this has a longer barrel length which will give better accuracy? This and a few 430 round mags should do me well for two years.
What do you all think about these two and which would you go for? I know it's more than I wanted to spend but I think I will get good use out of it. As for the fact it will be two toned I am not that worried as I will cover it in camo tape and probably keep it on constantly as it will only be used at sites and my garden where nobody will know.
I'm not sure if all sites will use equally good guns, my site has been going for about 20 years apparently so I'm sure they've got money to fling around, it might not be the same for other places.
But buying your own gun, even if it's worse than the hires, it's a plan worth doing until you can get UKARA, because it'll save you a huge amount of money. Hiring a gun costs more than taking your own, at my site, taking your own gun saves you £20, so if you buy a gun for £150 you'll have made up for it with just 8 days airsofting.
Also, with regard to the magazines, a hi-cap mag is a hi-cap mag, people don't count their shots, you can utilise a 300 round one just as well as a 3000 round one, when it runs out, fill it up! Or buy more.
I run around with 10 mags holding 30 shots, so mag capacity isn't something you should worry about at all.
Moving onto the guns, don't spend more than £200 on your first gun. Spending £400 plus on an awesome gun that even I wouldn't buy because it costs too much and then having to paint it fluorescent green would be an utter travesty to man kind and a waste of a beautiful gun.
Get something like a G&G or ICS M4 with a plastic body, they're fantastic starter guns and will probably last you your whole airosfting life, they also contain the same internals as the more expensive metal versions (like what my site use) so you can have fantastic performance for a fraction of the price, if you're not getting the range you want, stick a tighter barrel and a new hop rubber in.
It makes more sense to get something cheap if you're going to have to ruin it by painting it green/blue/orange/whatever and then once you've got UKARA when you turn 18, you can splash out on something amazingly, awesomely, truly spectacular like those mad £400+ guns you've linked us to.