If I had £5k for a TT bike, I would not be averse to letting the Storck Aero 2 put a smile on my face. With a budget of £5k though, my options would all be pretty tasty, no?

For £5k you would have a lot of options! Argon 18 E114 would be nice! http://www.argon18bike.com/DATA/MEDIA/764_medium.jpg