Track frame around £250

I'm going to be in the market for a new frame soon, and have about the same amount to spend (£250).

I've always quite liked the look of these. I've seen a few around london, who's got one/ridden one, and what are they like?

+1, really like the look of the nelson but i'm put off by the red, white and blue... does anyone ride the nelson, what's it like?