as the pans get old the non-stick does become less effective; you can get replacement pans but they are expensive.
I slide a flat wooden spatula down each of the 4 sides to release the sides, then turn it upside down and give it a few sharp shakes; the weight of the bread usually does the job then. If that doesn't do it you probably do need a new pan.
have to admit afterwaiting tree hours to bake it I was a bit sad that it didn;t come out.... but it really does live up to the cliches! Best bread we;ve ever tasted - like a savoury cake witha biscuit edge