I've read the comments above. I often buy a ranger or rover ticket and haven't had problems buying one at a ticket office. I always take down the code if I can find it as this may help the ticket office clerk. As far as I was aware TVMs don't issue them (certainly not the Northern ones) but I read above that you can buy some from Virgin TVMs. They can be issued on-train but is it advisable to try this if you are in a penalty fare area?
I always have the “paperwork” with me when I travel in case of challenge by a staff member who says “where are going with this, I’ve not seen one before”. I take the Today’s Railways Rover Ticket Guide Britain and Ireland which comes out annually with the magazine, but which is of course not an official rail industry publication. I also print out the relevant page from National Rail Enquiries (which may not be up to date) or the GB Railrover Guide
www.railrover.org, which again is a non-industry site and there is a disclaimer suggesting that we check the information for accuracy with the TOCs.
Many but not all TOCs produce rover/ranger ticket leaflets (or used to before they started cutting back on printed information) and some TOCs are better than others at promoting these tickets. There's also the ever-helpful Barry Doe! Does anyone have any advice as to the best way of dealing with these pitfalls?