First bike
My advice would be to bide your time, lurk around on here and decide what you specifically want, then aim for it.
The best retro builds take both time and serious cash. You will get far more satisfaction from buying a really nice frame, then gradually sourcing good parts, both as and when you can fund them.
£150 will not buy you much-full bike wise and it will undoubtedly be heavyish, not that fun to ride, or just plain tatty and worn out.
A nice Orange frame alone will cost at least £120 for a half decent one, but more likely £150-£200. Good wheels sets start at £80 ish, a half decent build would be £400 minimum, without going mad.
Ebay could be a better source for a bargain.