It's a lovely old thing. But the way we've all seen prices plummet of late makes me think you're aiming a bit high. I reckon 150 - 175 might generate some interest (though not from me I should add).
Have a look at Classic Lightweights entry for Frank. Interesting about your frame number maybe. Less so if you compare your frame's lugs to those which he preferred.
I wonder if yours is "badge only" job?
Have you any provenance?
Love it. I've heard of the Grand Tour model but info is pretty scant. Looks a nice old thing - I think it's 531 plain gauge - that suicide front changer puts it right in the 50s I believe. Thank heavens it's on the other side of the country!