Bike Build reccomendations

Bowman Palace R, Kinesis Aithien, or Condor Italia RC (assuming you're looking at rim brakes)

Don't take a carbon bike in a Cat 4 race. There are too many crashes.

What you want is a proper alloy racing frame, like a Canyon Ultimate AL, Bowman Palace, Cinelli Experience, etc. Plenty of stiffness where it counts and not as fragile as carbon when push comes to shove.

I tend to agree with Tjuice. Go Planet X,Canyon etc and get a all around good carbon build with mid end mech and decent wheels. For 1.5k you can get an awesome machines.

So, you have a groupset and want to spend a further £1500 on building a bike.

You don't say what your groupset is so I'm going to guess it's Shimano.  Your best PM option is Stages but at £400 you aren't leaving much for the other bits so I wouldn't if I were you.

Bars/stem/saddle/seatpost plus tape and cables will set you back around £150-200 I think.  So lets say you've got £1350 for a frame and wheels.

I'd say get a Cannondale Supersix Evo frameset, second hand, either on its own or as part of a bike that you part out.  There are loads of them out there and they are one of the best race frames you can buy for very reasonable money.  That should leave you about £5-700 for wheels and there's a whole world of options available for that money including hand builts.  If you want to go light, personally I really rate the BDop lightweight alloy build kit which is under £250 and builds a 1350g set of wheels with good quality hubs and spokes but you might need to pay someone to build it for you.  If you want deeper rims I also like Far Sports carbon wheels which can be had for around £500 at various depths.

If you don't want to go second hand get a CAAD12 frameset or alternatively the Kinesis Aethin which is similarly a race frame.

This is obviously only one route, there are loads of options if you buy a second hand frame and are patient enough to wait for the one you want to come up.

Giant TCR Advanced.. great value - you can probably find last years models (almost exactly the same but different colour ways) at a decent discount too potentially allowing you to up-spec for the same money..

In fact here you go.. https://www.bikeproracing.net/search/?Page_ID=3610&refpid=4&id=650029&gc...

Ultegra spec for under £1400

Strange that you've not had any responses.

Perhaps I'll kick off with a couple of thoughts:

1) If you are set on building your own bike, that's great!  Enjoy it.  I have put together loads of bikes in my time - mostly bringing an old bike back to life (sometimes an old frame with brand new components; sometimes (usually) and old frame with mainly used components), but also doing a complete strip-down and rebuild of a current bike.  If you have the mindset for it, building a bike (especially with a set of components you have chosen yourself) is a real pleasure and you really develop a deep understanding of what you are riding (and how best to maintain it).

2) However, it is likely that you will not get as much bang for your buck building your own bike from components as you will buying a complete bike new.  The bike manufacturers have much better buying power than you do, so they will buy all the components at a fraction of the price you would pay, and so they can put together a package that costs less (to you) than you would pay for all the separate components.   ...Unless you are buying second hand components or have a lot of components already...  But even then, buying a second hand bike might still be better value.  You might find that you can sell your groupset and add that to your £1500 budget and get really quite a good brand new bike, especially if you can find a sale deal somewhere (e.g., last year's model).  I've just taken a quick look at Planet X and their EC-130E with SRAM Force is £1500; Pro Carbon with Ultegra is £1200.  And Ribble have a whole bunch of bikes sub-£1500.  You can even get a carbon fibre Canyon Endurace with Shimano 105 for < £1500

Power meter might require you to compromise somewhere, but especially if you are happy with a one-sided option, prices are getting ever better.

Have fun choosing what you want to do, and if you do go for self-build, enjoy it.  It's quite special having a bike you've totally specced and put together yourself.

And best of luck with the racing.

Let us know how you get on with your decision.