I had a look at the spare sliding door mechanism that I've been hoarding. At the forward latch, there is a hook, spring loaded and slightly bent, and a sliding "bar" directly above. When the door handle is turned, this bar retracts a bit allowing the hook to move up in the female portion of the lock on the body frame. The rear latch is opened at the same time via the bowden (sp) tube/wire and the door pops out, driven by the spring on that "u" hanger thingy. When the door is closed, the latching of the rear catch causes the bar thing to slide forward on the hook, hopefully at the same time the hook slides into the female bit. When the hook and bar are in this position and out of the car, they can still move up and down, (they are spring loaded down), but I guess that when in the female slot, there is no room for both of them to move thus holding the hook down, but when the bar retracts... Gerry, maybe that bar is not moving in your case. You can activate the whole lock shebang when the door is open by moving the rear latch mechanism, see whats going on. If you decide that you need to see more, warm up th e door panel before attempting to remove it. I think its cold where you are now, and the plastic bits that connect the "oh so fragile cardboard" door panel to the door are a real bugger to pop out when cold.

Alistair