I am looking at getting back into road bikes after a number of years and need some advice to which is ideal. My budget is about £550 but can go higher if needed.
I have narrowed it down to six bikes. I have included links.
All bikes in that price range are going to be of similar quality. As such the only real way to find what will be best for you is to test ride a bunch of bikes. Then buy that one that fits best, rides best, handles best, appeals to your aesthetic values, and fits your budget.
The Scott has the lowest spec group of the bunch (7 speed tourney?) - I'd probably skip it unless the price was much lower than the others. The Cubes with Sora groupsets (9 speed) are the highest spec. The compact cube has a 105 crankset; I don't think many name brand bikes in that pricepoint come with 105 level cranks.
The 2300 groupsets (8 speed) are decent but not as nice a Sora. I can't comment much on the framsets - I hear that the cannondales are nice. I drove a rental Specialized Allez last hear in Hawaii, it was good once I adapted to the geometry.
Bike shopping via the net is hit or miss. If you are unsure of what works and what fits, its best to be able to try before you buy.