If you have Ł1000 to spend then you could end up with a lovely bike. I would echo the comments on here about the Shimano 105 groupset and the aluminium frame. I have just bought a Bianchi with a 105 groupset and an aluminium frame for Ł775 and am really pleased with it so I am sure if you are sensible and shop around you will get a fantastic bike.

I am also a large guy - I am 6ft 3 and weigh about 15 stone and I cannot stress enough about trying the bike before you buy! I have long legs compared to my body and there are very few bikes that I feel comfortable on. I always struggle to get a frame that has a tall enough seat tube without having a long top tube meaning I am stretching too much for the handlebars.

Go down to the bike store, look at the bikes, take measurements of the frame and make sure you get a decent test ride (once round the block is not enough!). Also, don't be pressured into buying, the worst thing you can do is have a salesman convince you to buy the wrong bike. Not only will you be disappointed with your choice but the chance of injury is greatly increased.

Happy shopping!