Paul’s bikes sometimes has good deals in carbon framed Cube bikes. That said I nearly bought a Caad12 105 disc from them but found a similar offer in my lbs so bought from them instead.
Carbon isn’t the be all to be honest – my Caad12 replaced a carbon fibre bike and I don’t feel I’ve downgraded. Frame weight is similar – I’d say I’ve lost a tiny bit of stiffness in forward drive – but gained a more fun bike handling wise. It’s still pretty razor sharp – helped by upgraded wheels and tyres (nothing too fancy)and now Ultegra Di2.
Bike cost me £1200 in the sale down from £1700. You might want to look at Boardman too if you particularly want carbon – sometimes they have good deals.
Some people will claim rim brakes are as good as hydraulic disc brakes but in my experience they just aren’t (4 different sets of rim brakes vs Shimano hydraulic discs) – I’d prefer to have an alloy disc braked bike than a carbon rim braked bike.
Planet X sometimes have good deals on carbon framed road bikes too thinking about it.