A month ago I (foolishly) purchased Super Off-Peak Single tickets from Bath to London Victoria Station for Sunday May 12, departing 9:06 AM; I found the route on nationalrail.co.uk, and I was transferred to the GWR site to book.
I see now that this was silly - I assumed I was getting a cheap rate since I bought early, but didn't realize I should wait until tickets marked "Advance" showed up.
Today I was curious about how much money I lost, so I searched for the same route on the National Rail site and the 9:06 AM train is no longer listed; any idea why? I see the service notice below which I didn't notice when I first booked; could this be related?
"Buses replace trains between Bristol Temple Meads and Swindon / Westbury and also between Swindon and Westbury on Saturday 11 and Sunday 12 May"
I wish I'd found the seat61.com site sooner - lots of good info there!