Hi Joe, if its the hartal door lock thats fitted then ever one is having problems with it, ive had 3 new ones on my coachman now and its having another in 2 weeks when the van goes in for its service, swift are one of the hardest hit and loads on this forum have had problems.
Tell your dealer you know there is a problem with this type of lock and insist they replace it for you, if they still will not then contact explorer and see if they can help.
If it not fitted with the hartel lock then i think you may have to pay yourself as no others have inherant faults as far as i know.