I thought that I would finish off my build blog with a summary of things I would do differently. To be honest there was not too much.

Car spec...
Full hood? - I never installed the hood sticks and therefore won't use it (I will use my half hood). If I did it again I may try to negotiate with Caterham to get a half hood instead.
I have no regrets about my lowered floor, mono steering wheel and leather seats.
The FIA roll bar was probably a bit over the top, but I like it (it makes a full hood a very tight fit)
Carpets - I fitted carpets in the boot but didn't fancy them for the cockpit. (I would say don't bother).
12V Socket - I fitted my own (it only cost a few quid, and is fairly easy to do)

Tools in the manual that were not needed...
Circlip pliers which went unused
Crimping tool - used once and could manage without
(A good deadblow hammer was a very handy tool occasionally)
Low profile Jack - I bought a rather heavy duty Jack. A low level one would have been much better.

Other thoughts...
Bonding wings - I bolted my wings. Some folks bond them - I could see the advantages.
Administration - takes more time than you think. Getting Caterham to do the IVA cost £425 (in addition to the IVA cost) but saved a lot of hassle. They do any retest for free.

More care...
Radiator bobbins - don't torque them up to much they break.
Ecu bolts - so do these.
Brake fluid - is nasty and ruins paint. Don't let it splash.

Discoveries...
Fancy plates (online) - is a good place to get cheap number plates (and you don't need documentation)

Soft bits for sevens - the half hood, shower cap and tunnel bag seem very good investments (L7 discount, but buy early, they get busy later in the season)

Premier paint guard protection - I paid them to do my rear wings as there was no template. However, next time I would have a go fitting the plastic myself.