I didnt understand by "edge" computers or any of the others you listed.... But i checked that company "hi-grade.... And wow what a rip off!i wouldnt so much "quid", as you brits say, for those computers.
in regards to the dell or hp being better, id stick with dell as i find them to have low prices, sleek looking pc's and better performance than the hp.
if you have dell in the uk, id go with them.
if you can build pc's yourself try to get cheap parts from a uk online computer store or ebay.uk