I was going to suggest you wait until the end of April when the Team Durango DEX410R is supposed to get released. I think it'll be around £250, which leaves you with £125 to get the rest of the stuff, although it'll be tight, you'll get one hell of a car (from what I've read).
Other than that you could look at the B44
http://www.modelsport.co.uk/?CallFun...n&ItemID=28600
or, the 2wd RC10
http://www.modelsport.co.uk/?CallFun...n&ItemID=18469
You may also need to buy tyres if the ones that come with the kit are no good. So bare that in mind.
I'm no expert, and know very little, but that's my opinion. on kits.
Motor wise, do you know what kind of track you'll be racing on? I know an indoor track where they recommend not using a brushless motor with a lower turn of 6.5, it's just too powerful for the track.
Battery wise, you may struggle to get a charge and lipo's within your budget (I may be wrong), so it might be worthwhile getting an ESC which can take NIHM and Lipo, get NIHM batteries and you could upgrade later if necessary.
Just to give you an idea, I bought...
Lazer ZX-5 RTR (which is one of the cheapest) £179
6.5t Motor £49
ESC £90
2 x NIHIM Batteries £60 (£30 each)
Battery Charger £35
New tyres £10
TOTAL: £423
That's for a running car, but not a competition spec car. Great to start with though, and the advantage with the RTR is that it's ready to roll. it comes with a stock motor and esc etc.
As for Lipo's a set of cheap Lipos is about £40 I think, and a charger about £80 (from what I've seen). So 2 sets of batteries and a charger will set you back about £160 alone. That's why many people use NIHM because they are cheaper.
If you're after something decent, that I'd probably say go 2nd hand. I've modified my Lazer ZX-5 to be race ready, and it's probably cost me another £200. If you buy 2nd hand, someone will have done those upgrades.