figure $500 US for his frame, but that includes import taxation etc.. so figure more like $350-400 US by the time you factor in how much more the poor folks in the UK pay for everything.

That's still fairly entry level for a "racing frame" though.
Look at good stuff like Cervelo, Kuota, Kestrel, Felt, De Rosa, etc.. and you're in the two-grand range, US easily.
then add another one to two grand for the grouppo, then add a grand or two for a wheelset and tires, then more for bars, stem, seat post and saddle, pedals.
If you really intend to "race" then you're getting into some money. just a casual observation.
The kuota kebel red I am looking at buying is about six grand complete. more once I add some tweaks like profile CGT bars, a computer, pedals, etc..