The difficulty for Cam & Dursley and Yate is that they accomodate only four coaches so using a five coach voyager is likely to fall foul of a policy or two.
This reminds me of an occasion a few years ago in Virgin days when I was taking a Voyager from Penzance to Temple Meads. It was already busy in Cornwall so the Guard announced that they were attaching another set at Plymouth, meaning that passengers (such as me) who were currently sat in seats that were reserved from points up the line could get off at Plymouth and join the extra coaches which were all unreserved.
Then as we approached Plymouth he announced that this was in fact not going to be possible, because due to planned engineering works the train was going via the Severn Tunnel and timetabled to stop at "Bristol Patchway" instead of Bristol Parkway (we knew this from his announcements, but it sounded like someone responsible had only just noticed/remembered). The platform wasn't long enough at Patchway for a 9 car train, so the extra set would have to run empty till after the stop at Patchway -- he said it was for reasons of Health and Safety, in case anyone tried to get out where there wasn't a platform. I said to the bloke next to me, "Is this the first day they've run a train service?"
However, a couple of minutes before we left Plymouth, he announced that the problem had been solved -- they were going to miss out Patchway, so anyone for Patchway should now change at Temple Meads. Then there was a mad scramble while half the passengers, including those who'd just got on the train, retrieved their luggage and found seats on the empty set.
So that's how I learnt that Voyagers don't have
SDO▸ .
