This product, though the price has varied, has existed for many years, I do not know when it was introduced, but it would not surprise me if it was 10 years or longer ago. This ticket type
was called "Business Saver Return" and the code
was BVR.
I see "Simplification" has been mentioned, and what happened here was no different to what happened elsewhere and tickets were put into one of three categories, Off Peak, Anytime and Advance. Within the Off Peak category, there is a type called Off Peak Return, and that is what this ticket is.
The
normal 3-letter code for the Off Peak Return ticket is 'SVR', and this applies to the Off Peak Return from York to London priced at £157.00.
Sometimes EC will sell these Off Peak Return tickets at a discounted price, in order to encourage people to switch from Grand Central, the discounted price is not much higher than the GC Only Anytime fare, and is valid on the Grand Central trains and gives much more flexibility, being also valid on East Coast (and EMT, etc...) services. When they do this, they do not actually reduce the price of the 'SVR' and sell a ticket using the previous code for this ticket, 'BVR'. The product is identical, but the fare is lower.
As for the restrictions, ATOC claim that
the new names describe when you can use a ticket, so in theory you can simply look at the name (Off Peak) and then you know when it's valid. If you think that is misleading, I would encourage you to contact your MP, the DfT, Passenger Focus and any other person/organisation you feel is appropriate.
The 'BVR' appears to have the restrictions that used to apply to the 'SVR' under NFM08 (I didn't check NFM09), it is likely that this has not been updated to reflect the new timetable, as in theory the current 'SVR' and the 'BVR' are the same product, just with a different price.