Can Grahame's acquaintance not simply buy a ticket from Dilton Marsh even if boarding at Westbury? I'm assuming a return ticket; so on coming home, can get off at Dilton Marsh if practical or Westbury if not – all for the same fare, if I've understood correctly.
That's probably what I'll be recommending. It leaves a couple of issues
* As the
TVMs▸ at Westbury only sell tickets starting at Westbury, it may mean queueing at the (one) ticket window
* Done on a regular basis it will distort Dilton Marsh's figures
* On Advance tickets, only those with
DMH▸ connections will be offered; I recall the difference on a Gatwick to Chippenham v a Gatwick to Melksham being 3.5 time on one occasion (lowest cost)