Grahame, I know you have Issues with the Melksham service (RIGHTLY SO) but as Upwey is a SOUTH WEST TRAINS station, it's not in SWT▸ hands to improve the Swindon Service, Now if stagecoach had won the Greater Western franchise!!!!
I didn't intend to call on South West Trains to improve the services from Upwey to Melksham / Chippenham / Swindon - rather I was pointing out a traffic flow that's acknowledged by the sign (and it's one of many such traffic flows) to and from the South coast - from Weymouth to Southampton, and the intermediate hinterland such as Yeovil and Salisbury, up to these major population centres in North Wilts.
And yet ... having said that I didn't intend to call on South West Trains, there would be a huge logic to them providing a service to North Wilts via Trowbridge. After all, they have a full diesel depot for servicing suitable trains at Salisbury. I won't go too far in this thread on that technical logic - it has been raised in the past and I expect it will pop up again!