What kind of riding are you looking to do? If you can find something with the updated Claris groupset for 2018 or better that'd probably be a big factor. There are a few with the older version, which could still work well if there's no other options;
http://www.chainreactioncycles.com/vitus-bikes-razor-road-bike-2017/rp-prod147649 (10% off with £22 British Cycling membership)
https://www.evanscycles.com/pinnacle-laterite-1-2018-road-bike-EV299413
http://www.halfords.com/cycling/bikes/road-bikes/carrera-vanquish-road-bike-white (also 10% off, only a couple of sizes)
http://www.gooutdoors.co.uk/calibre-rivelin-road-bike-p343886
http://www.gooutdoors.co.uk/calibre-lost-lad-road-bike-p400012 (decent option with disc brakes if they see themselves riding in the wet a lot, but the sizing options seem kind of weird, might want to actually check it out in a store to see what's going on)
https://www.merlincycles.com/merlin-pr7-bike-shoe-pedal-deal-99308.html (more extreme limited sizes)
https://www.merlincycles.com/merlin-performance-pr7-r-road-bike-2016-88021.html (a bit more aggressive, older style sora, also limited sizes)
http://www.tweekscycles.com/bikes/road-bikes/genesis-delta-10-road-bike-2016 (only 56cm, and only one left apparently, but probably the best frameset)
https://www.rutlandcycling.com/bikes/road-bikes/mekk-pinerolo-se-0-1-2016-road-bike-white_378394
As for how to pick between them... size is the most important thing, as ever. But it's kind of hard to differentiate frames around this price point, I'm sure they'd all be fine for a beginner really. Mudguard/rack mounts are personal preference. But a tapered headtube would be nice. It looks like the Pinnacle uses a similar 'minimum triangle size' formula similar to Giant (and the PlanetX Pro Carbon) which is supposed to be quite stiff, but I'm not sure how much weight I'd put on that.
Actual Shimano chainsets are typically a bit better, Claris 2400 is "only" octalink [edit - apparently I'm mistaken here, it can still be square taper] but that does have the advantage of a fair bit of weight saving and stiffness compared to square taper. Wheels make a big difference, with something from Shimano, Mavic, even Alexrims probably being more solid than some nameless 'own brand' wheelset, but even those would probably do fine to start out with, just have to bear in mind that it's something that could be upgraded.
Aesthetics is important too, but often overlooked. If you like how your bike looks you'll be more likely to ride it, no matter what some item on the spec sheet says it should make you feel. Weight wise they're all going to be around 10kg, think the Vitus is the absolute lightest out of the box at 9.6kg but it's not really enough to be the biggest factor.
Ultimately I imagine it'll come down to local availability and cost, however.
