All was good until about a week later when the rear-door wouldn't open anymore... oh no!! I climbed in the back and had a look. Since the door was effectively locked shut then everything is nasty and difficult.
I was certain of the cause... glass in the latch mechanism. How to get that out?! I tried lots of stuff for many hours and here is a summary (with success!)
Step 1: Check the Easy Stuff...
The latch and electric locking mechanism is at the bottom centre of the door and has a cable running to the door handle
Try locking/unlocking the car. The white piece of plastic on the latch mechanism moves up when locked and down when unlocked. No problems with that for me.
Get someone to squeeze the outside handle - the cable should pull a lever on the latch/lock to the right. Try pushing it directly to see whether it can move further (the cable could be stretched or not attached properly). Again nothing so simple for me.
The picture of the lock/latch mechanism was taken much later when I finally got the door open.
Step 2: The Door Latch
I tried breaking the black plastic on the latch and then shoving in a bit of wire. I hoped to dislodge the glass but that was a fail. I couldn't see inside the latch - I didn't know where the glass was nor the internals of the latch. Better try something else (2 hrs later!).
Step 3: Break Some Plastic
Step 4: The U-bolt
Arrrgg it's attached with countersunk heads... luckily there is a toothed-washer underneath each of them so there's enough to grip with some long nose pliers with nice sharp teeth (I tried screw driver bits but they were much to long to fit in the gap)
Grip hard and turn!
Step 5: And Push
Now you can remove the latch & lock mechanism from the door (undo 3x 10mm bolts) and inspect. I actually undid the latch bolts before opening the door (since they were easy to undo and I hoped that the door would somehow open without attacking the U-bolt screws) but I think I needn't have.
The other 2 photos were taken once the U-bolt was freed from the latch
Step 6: Fixed!
Sucked out all the glass fragments remaining in the bottom of door (duct-taped a piece of poly-pipe to the vacuum cleaner) and put everything back together. What a relief, all is good!
If it was broken, I think the order code is 69350-28110