I know it’s not a particularly impressive budget
You’d be surprised. It’s such a hotly contested price point, that yields exceptional performance per £ IMO. Much cheaper, and the weight and cheaper components tend to blunt the ride too much, more expensive and you’re starting to spend money on marginal gains.
I’d not bother with carbon at £1k personally, there’s a lot of good racey ally bikes out there with frames almost carbon weight anyway, covered in half decent groupsets, wheels and finishing kit. The Planet X deal might seem a no brainer on paper, but you only need do a bit of research on t’internet, and it has its detractors.