I could give that a home - very nice. Seller's wrong to say "good unrestored condition". He's photographed the "Renovated by Allin Cycles" decal! Although that was probably done in the 50s or 60s.
I'm unsure but the sticker looks like a "big it up" addition.? More research needed. EDIT all I've found is a mention on another forum that refers to 531 butted. Phillips catalogue anyone?
Yes it's small, 19 or 20 inch? That head badge could have been done more elegantly - maybe trimmed to fit around the spears of the lug. That's what I would have done. And, given how small it is, I think it may struggle to get near the estimate?
"stronger than the wood itself" - an oft used ad byline. Can it be true - it's PVA we're talking about. I wouldn't trust it on a rim - subject to many huge and various stresses.
I thought I'd seen this in another guise, but couldn't find it. Well spotted.
And it's down to £20! Given there is some doubt about its authenticity that's about right. Still, looks a decent enough frameset.