I have bought quite a lot of my kit from Hampstead brewing, it is all fairly solid and has decent immersion heaters in. 2.4kW in the HLT and 3kW in the boiler.
Have a look herehttp://www.hamstead-brewing-centre.co.uk/itmidx55.htm
I have their Boiler, HLT and sparging arm which are all great, and would happily recommend them. It's 30L as well which I think you will find more practical.
Their full kit is Â£299.00 with insulated Mash Tun, which if you are starting with nothing, and like me don't want to build it yourself is a reasonable buy I think.
You could always buy the essential bits now and add extra bits later if money is tight. I bought my boiler first and did extract brews for a while until I stepped up to AG.