£1200 Road bike - should it be fully carbon?

Tell me about it! Putney Cycles let me use the full Cycle Scheme 'allowance' and pay cash for anything I wanted that went over the grand. I imagine other shops in London wouldn't have an issue doing the same so at least that gives me a few more options.

I know this is an annoying 'how long is a piece of string' question but sort of money would get me a decent first road bike that would keep me satisfied for a year or two. You know - something to learn the ropes on? £1.5k do it?

Try spending £1.5k on the ribble bike builder, with the racing sportive frame, as a base. Should be able to put something nice together.
The one I've put together in case of an unsuspecting lottery win consists of:
Racing Sportive frame + forks
Campag 11 speed Chorus Groupset
Campag Neutron wheels
(mountain climbing set-up. Lots of gears and light wheels)
and comes in at just over £1.9K

Wilier Mortirolo

+1
or for the Alu lovers, I'd be tempted by this Pinarello.
http://www.evanscycles.com/products/pinarello/fp2-105-2009-road-bike-ec017689
£1.5k with Shimano 105