The lock on the hab door of my Autotrail Tracker has finally given up. It went a couple of time s last year but we were able to fix it. I think sometrhing inside the barrel has gone . You cannot even get the key to go in. It looks like a Zadi barrel but all the ones I have seen on ebay and the motorhome accessory sites have a short flat piece that goes into the interior part of the handle/lock. My one has a longer stub. I cannot even find the exact same complete lock set. Any ideas