I'd recommend the G&G MP5A4 (I believe it's called the PM5)
They do them for £250 but there's also a Sportline version for only £130 or so. The only difference is that the upper receiver is also constructed from (very high quality) polymer. As usual with G&G guns the internals should also be excellent.
It probably comes with their green hop rubber which is awesome too. Plus, the stock should give you a huge battery space.
You could pick up a battery and charger for it for around £30 max I think, and if you don't mind the wait you can order an 8 pack of MAG MP5 magazines from HK retailer eHobby Asia. They're only £30 or so, whereas in the UK they are £55/£60.
I really wish I'd bought this gun myself as I've heard lots of good things about it. I bought a Classic Army MP5K Sportline Starter Kit as my first gun which cost like £140 but I honestly wish I'd known about the G&G MP5.
nah, get a G&G raider S (for short). quite short, very well made, nice rails, good looking gun and it won't break for a loooong time. That would be my choice, because mags are cheaper and hold more