Restriction codes are the same for outbound and return legs of tickets (with the exception, I suppose, being when you are using a ticket that cross-references another code for "journeys from London St. Pancras" and your outbound journey went into Kings Cross, or suchlike). Certain pairs of restrictions are the "opposite" of one another, for example SVR Shotton to London Terminals is VK, and SVR London Terminals to Shotton is VN; these are the mirror image of one another.
yes - thank goodness - if I was travelling on a VK restricted ticket I would have been in the wrong.