Dont bother with that PC.
have a look at the special offer page, if you have an Aldi nearby, the pc they are selling is very good value.
Also have a look at Dells website, They sometimes do some good special offers. But they are a night mare to update in the future, because they use their own custom bits. So you pay 3x the amount for the same component.
Mesh computers are quite good too.
http://www.meshcomputers.com/updated/index.htm
But if it was my £1100, I would build my own pc. But if you need all the software provided with the pc packages, This would not be a good option.
edit/ I forgot to tell you.
DO NOT buy the pc, just because it has the latest most fastest CPU out of the lot. Because thats the only thing you are paying for. That 3.4GHz CPU costs about £400. and a 3Ghz cost about £150. But the difference will be so marginal, even an enthusiast would be able to tell.
So above 2Ghz would be perfectly sufficient for any application on the market today.
Dont listen to the sales man when he says to you that you need the fastest, because it will last you the longest. That is not true.