Hello mate,
Although the Quality release is rarer I don't think either of them are worth anywhere near £1k, not in terms of rarity but desirability. I think these are inflated prices that seem to have happened largely on UK dealers sites. Realistic price on either would be £300 odd I would of thought. Also, although you have two dance sides on the Quality one, the US release's sweet flip perhaps carries some weight with those collectors? That might be way prices are similar on both.
Personally I think it's a great 45 but maybe the dancers don't agree? The 'Anyway' side might be more appealing on listening to it again - 'SIBY' has a very tricky beat - the few times i've played it you often get the great shufflers doing their thing to it.
As for the stop label, Athen Rogues, Endeavours and Berkshire Seven all make me think it is a gen 60's - early 70's label - maybe someone can shed more light on it? Nashville, Tennessee according to label.