I purchased a YP first advance ticket at Berwick upon Tweed ticket office for a cross country service (for a different part of the country, not ex Berwick) for my son, who is currently on that train. The ticket clerk mistakenly issued the ticket as a standard. When I pointed this out she issued an excess to first and changed the reservation coupon to first. The ticket examiner on the XC service is claiming the ticket is invalid and advances can't be excessed and Berwick have got it wrong. I'm guessing Berwick have got it correct, as how could the system issue the correct excess? (The excess ticket brought the total price to what the first advance would have cost). Who is correct?