There is an actual company called HK.
The real gun company is called H&K.
Go for a G&G rifle, their starter range are good enough for the longest playing airsoft veterans to buy and be satisfied with, they are spectacular value for money, have very good performance and the build quality is faultless, I expect what you pay for a G&G starter gun from some of the higher end guns in the £300 bracket and suffer greater disappointment. There's also a good range of choice, M4s, AKs, MP5s - all the most recognised platforms.
You'd be looking at £140ish for a standard M4 + batteries and accessories etc.
One thing I will say though, hiring is more cost effective that buying a two tone gun.
Let's say it costs you £40 per trip to hire, you need to do that 3 times to be able to buy your proper gun in real colours, so you play 3 times for £120 and then you buy a properly coloured gun, that you actually want.
If you buy a two tone, it will cost you more than £120 to buy the gun, you then still have to pay the fee to play on the site, which is usually around £20 per trip, so you'd be looking at about £150 for the gun, + £60 for your three trips, that's £210 before you even get UKARA.
Then once you get UKARA you'll want a proper colour gun, so you'll either paint your two tone and have to deal with it - in which case fair enough, if you don't care about getting a RIF then definitely get a two tone.
If you're unhappy with a two tone and want a proper RIF though, then you'll either buy a second gun, or sell the first and use the money to buy the second, both of which will obviously cost you more money than just waiting until you've played 3 games and buy a RIF from the off.
So I'd say just stick with it until you have UKARA, that's what I did. Is waiting really so bad? It gives you more chance to read around and see what you want to buy, as well as ask people at your site, watch videos on YouTube, ring the retailers etc etc.