My Smudge who is missing at the moment would only eat human tuna - which I could get anywhere or Wilkinson's own make of Tuna pouches. Sometimes when I went into Wilkinson's they only had a few on the shelf and I asked at the customer service desk if there was any chance of ordering 50 at a time and coming to collect them when they had their next delivery. They phoned me and I would go pay and collect. Not sure if they have Felix tuna or even if you have a wilkiinsons where you live. You could also try Sainsburys and co-op as Sam and Mark have seen them there - pop in and ask if thye will save some for you like they did for me at Wilkinsons.
Good luck.
Mary