new bike for tt's

As someone who is planning to do duathlons - should have done one last year (dunno if I'll do one this year at this stage), it seems to me that something TT specific is a bit of an overkill for the shorter distance. There's loads of aero bikes to use clip on bars and then just ride as normal, including Planet X's N2A, Giant Propel Advanced 3 (£2K), Cervelo S2 105 (around £2K) and the new redesigned Felt AR4/AR5. The AR5 has been of particular interest as it's cheaper of the two AR models (with 105 at £1,799, the AR4 Ultegra at £2,499). The seat post can be turned around to provide closer reach/better aero position if using clip-on bars. However, I guess with the N2A you do get Ultegra and carbon clincher aero wheels with 1p change from your budget.

I bought a TT bike at the end of last year for racing triathlon on, and relegated my previous road bike (an entry level, pretty horrible) Dawes to commuter/shopper/odd-jobber.

I think I made a bit of a mistake, in that I'm really missing a training/fast road bike for weekend riding and perhaps getting in on club run action.

So I would say, get a TT bike, but only if you have already a training road bike and a bike you're happy locking up places (if that's your thing).

If you think you're going to enjoy it and take part regularly enough then there's no harm in buying a TT bike at all, tri clip ons help but if you want to get a little more serious then they're not perfect, as your position is quite limited on a roadie, your time will benefit from the position offered by a TT set up.

Try Planet X - you'll get a load of change from £2k! But it depends where you feel your commitments lie, if you only have that to spend on either or, do think carefully about whether or not a road bike would benefit you more in the long run.