The thought did occur, Mario. Yes, it was a complete unit, and yes the fault must lie inside the door somehow. It's just a little bemusing that everything works fine until I join up the pieces. And it's not like it is just sticking. It stops dead, in the same position each time. The only difference between the old one and the 'new' one is that the old one would go from completely closed ( when I put it back in ) to fully open, and stop on the way back up. This one won't do that even.
To think, people believe the Chinese are good at making puzzles....

