Up your budget to around £400, depends on what riding your doing but a hybrid is a good all round choice, I use a s/h Boardman comp as the work bike and it is spot on.
Racing bikes tend to be a lot more focused and have a lot less comfort.
I have at the moment the Boardman, an On one Pompino single speed plus the Dawes tourer, it a nice mix for the miles I do (around 3500 a year)