help choosing first road bike

At this price point whatever carbon frame you choose will ride at a similar level. Most of them come from the same chinese factories, they just have a different name painted on the frame. Do your research, look at everything, try as much as you can and make sure it fits properly.
Aluminium doesn't make a great frame either so you're probably best off with something in carbon, titanium or steel.
The things to be careful of are the shifting and the wheels, if the gears don't shift well and the wheels don't spin nicely you'll soon get fed up with whatever bike you have.

Happy hunting.

p.s don't get too hung up on prices, most shops will discount.

+1 for LBS and/or cycle to work schemes.
Carbon isn't always the best way to go either: I hear it fizzably melts in the rain like prawn cocktail Skips.

Don't forget you'll want to spend some money on shorts, jersey, base layer, clipless pedals, shoes and a razor for keeping them legs all smooth.

Would have to second both of the above comments, I personally cannot overstate the importance of not buying "blind" online when it comes to a first road bike.

Go to your local store and talk to them about what you need, they'll be able to help you establish which bike(s) best suit those needs, plus you can test ride them too rather than discounting bikes based on online reviews only.

Most importantly, they'll help size the bike too, not just the outright frame size, but things like stem or crank length, and the position of the saddle or handlebar. That's something no amount of internet research will tell you.

As above, don't assume carbon is automatically "better". It's the fashionable choice, but cheap carbon isn't as light or stiff as you think, and I don't personally believe it's any smoother a ride than good aluminium or steel either.

The upper end of your budget will actually get you on carbon from the more-established brands, but that'll mean lower-end components. Don't get hung up on this, the majority won't need the benefit of having an Ultegra groupset over a Tiagra one, and who cares if you have a non-series chainring as part of the build?!

As for that BeOne bike, £850 for a carbon frame and fork, full 105 groupset, plus reasonable wheels and finishing kit is good value on paper, but I suspect what gives is the quality of the carbon frame and the build generally. Not for me, but then I'm the sort of person who would always buy a Sony TV over a Technika one... I'm sure Technika still sell a lot of TVs.

Sales generally take hold in the autumn, once the majority of manufacturers have released their bikes for the coming year, but you can generally find sale-price bikes year-round, particularly if you need a less-common frame size.

As an alternative in the affordability stakes, does your employer offer a cycle to work scheme? If so, you can get some decent savings buying a bike that way, although you are essentially limited to spending no more than £1000.

Otherwise, have a good search on here for advice. They often run their own round-up of road bikes at certain price points, and the old "what bike to buy?" topic is a frequent one on the forum too.

Above all, good luck with the search, and keep us posted with what you end up buying.

Carbon for carbon's sake because it was cheap is a bad way to go about getting a first road bike. If you are new to cycling a good relationship with a local shop is far more important; You'll get to try before you buy, get advice and have someone to go to when something goes wrong or needs serviced. Most good shops will throw in a year or mores servicing, and becoming a regular usually results in other benefits too.

These things are far more valuable to me than getting a carbon frame I've never ridden from a brand I've never heard of. What's valuable to you may be different. At this price point carbon isn't necessarily going to be any better than a good alloy bike.

Your first road bike should not be purchased online. You need to ride it before you buy it, and you need advice from a trusted and knowledgeable person who can see you on the bike. Focus on finding that person. Cycling clubs are a good source of referrals to local shops, bike fitters, and coaches who can provide that service.