Thanks, Bill. A few thoughts --
Like you, I'm not at all sure what a used Thorn Nomad (or Raven) might fetch in N America. May be one of those situations where, if you find a person who's looking for that particular bike, you'd get a good price. OTOH, of course, the scarcity of the Nomad means that they're not well known, and hence most people would not pay a premium for that reason.
C$1,000 is just a little more than £600. If we estimate that a new Nomad would cost, say, £2000 (~£2500 list less VAT), plus shipping (£200?) + 26% duty and GST ( = £2200 + 26% or £570) total £2770, or C$ 4600 rounded, then I'd ask -- could you ask about C$2000 - C$2500? Does the bike's condition warrant that?
Another reference point would be a new Surly LHT: at or over C$2000 with good specs and GST. You'd be offering a more robust bike with a Rohloff.