Incidentially, what would you say the consequences of a reduction in stamp duty are? It will inevitably increase house prices by the difference. If someone is willing to pay asking price plus stamp duty then they will be willing to pay asking price plus lower stamp duty plus the difference.

 Probably, but isn't there the other side of the transaction as well?  Some seller was willing to sell for 317,501 pounds, so he still would be ready to sell for that, wouldn't he?  It's a competitive market after all, and you're competing with other sellers who are selling their houses.  Seems likely it could end up in between.  But one likely will never really know, because you don't know what you would have sold it for, and there are other factors in an ever changing marketplace of buying and selling.