To anyone reading it accidentally, I should probably apologise for this thread.
Also inspired by the perception that, when bought as an add on, GWR▸ have tended to make the Bristol to Bath length of the GWR main line one of the most expensive in the country. (OK, probably justified by the engineering works...)
One of their most popular pieces of track, it's no wonder that they try & get as much revenue as possible from it. Always remember that the sole purpose of selling Advances is to fill seats that otherwise wouldn't be filled - and with Bath - Bristol being popular, they don't have to sell that many. AS an example, it is often cheaper to buy two off-peak day returns from London to Bristol (splitting at Didcot) than an Advance from Paddington all the way. And you get off-peak flexibility too as a bonus.
With a railcard, I've just looked at a return Bath Spa to Knighton versus Bristol Temple Meads to Knighton.
National Rail lists the fares as 'off peak returns' but allows travel on the first train of the day.
Bath Spa - Knighton: £49:75
Bristol Temple Meads - Knighton £35:35
So, a difference of £14.40
Here's a comparison on similar tickets from the two starting points to Swansea.
National Rail lists these as 'Anytime returns' (for the entire day, the site quotes an off-peak fare for later trains, but from Bristol, that's £39:65, so, £13.20 more expensive than the 'Anytime' fare that allows more flexibility.)
Bath Spa - Swansea: £33:25
Bristol Temple Meads - Swansea: £26:45
So, for Swansea, Bath cf. Bristol as a starting point adds £6:80 to the fare.
Incidentally, with a railcard, 'Anytime Day Return' Bath Spa to Bristol Temple Meads is £6.60. (No period returns available...)
OK, a popular piece of track, but GWR needs to look at the way that long distance travel that involves use of the Bath to Bristol leg is priced.
Perhaps this also bites other starting points east from Bath too.
Perhaps it's not even GWR that's responsible - some of these journeys are priced by either Crosscountry or Transport for Wales. (In the case of Bath Spa to Knighton, it's difficult to see the connection with Crosscountry...)
Mark