Jim, hello,
The main problem is access but the fitting and actuation of the latch and lock is quite simple and straightforward. The door handle assembly lips behind the door panel at one end and is held in place by the metal bracket shown in your picture. The bit of bent wire with the hook thing engages with another bit of bent wire on the door catch. The adjustable nylon prodder operates the catch and allows the door to open. I hope this is of some help but if it all seems a bit garbled well that's just the result of plenty of Christmas cheer I might be a bit more lucid in the New Year!