A load of rubbish, here is why I say that.
I go on to to the Great British Rail Sale website and type in Reading to Birmingham New Street.
I am told that tickets are available for £12. I am then directed to the XC website.
I then type in the journey (Reading to Birmingham), try various dates and times, only to find the cheapest tickets are £30.60 single (£61.20 return).
I also do the same for Reading to Cardiff Central.
Again, the Great British Rail Sale website tells me tickets are £20.
I go onto the GWR website, try various dates and times. The cheapest I can find is £38.90 single (£77.80 return)
Why is it always so difficult to find these promotional prices?