The Boardman in
Halfords for £999 seems a good deal, not sure if its more racey though.
Maybe it is, and maybe it isn't!
By going out and looking at possible answers before working out what the question is, you make it more likely that you'll get a bike that isn't right for what you want.
It's best to start by working out what bike geometry you need. Once you know that, you can look at frames that catch your eye to assess whether they can be adapted to fit you - using the right stems, seatposts, and other adjustments.
How do you work that out? You could either have a fitting (but make sure it is with someone who understands long distance cycling which will rule out most bike shops!) or work it out for yourself by getting a cheap bike, doing research and experimenting. The complication though, is that your ideal fit changes as you ride more, get fitter, get more flexible and get to know what you like and can't put up with. Therefore, a bike that seems right now is very likely not to be right by the time you start LEL.
Therefore I'd recommend that, rather than spending a lot of money now, you would be better to get a cheap / second hand bike, do some research, set it up how you think is right, ride it a lot, adjust things depending on how it goes, then have a fitting and choose a compatible frame. For LEL and audax in general, selection of groupset is probably not as important as getting the right bar tape!