I think that that's as good as denial from TfGM that they haven't issued any new instructions to restrict the sale of Wayfarers from certain ticket offices, as you are going to get. FoI replys are often worded like that. If they had imposed any such restrictions then you'd have thought that they'd have a record of having done so and responded to the FoI request accordingly. Despite what Sheffield ticket office may claim, the problem lies closer to home. Of course there could be a longstanding secret restriction on the sale of Wayfarers, that has never publicised anywhere at all, that TfGM have forgotten all about and that only Sheffield station are correctly enforcing, with every other station in the country getting it wrong....