I probably shouldn't pre-empt the exhibition, but I was at a meeting last night attended by a number of people who have already seen the plans; it looks like the store would be "fed", traffic wise, off the A350 - left turn only in, left turn only out - with store users from Melksham required to do a "U" turn at the traffic signals where the A350 and A365 divide - very close to the station.  The lights already have a U turn lane.