The first computer with the Phenom II X2 would run much faster in most applications (with multi-threaded they would probably be equal), although the GT 220 would be a bit faster than the HD 4650. I'd definitely go for the one at currys.co.uk, mainly because of the better processor. You said you had a £600 budget last time, so are you going to upgrade the first computer's graphic card to an HD 5750 for around £95? If so then that would be the best option.
So the first ones graphics would work just be a bit slower???
HD 5750 is ATI???