Market town? When the hamlet folk go shopping, they're going somewhere else?
Oh, of course. They're going to Brackley.
It does rather ruin the sense you get that the Lark Rise folk are always popping into Candleford: they probably almost never went there, having a perfectly good shopping town a couple of miles closer.
(And I realised another problem with the scenery the other evening - the corn fields aren't filled with poppies.)