Solution: drill a hole behind the number plate to access tensioning rod that drives the latch.
In my situation the latch itself was fine.
It was the 'button' mechanism which failed to pull the rod to unlock the latch.
Drill a hole of at least 6mm in diameter in order to be able to put screwdriver through the hole.
Position of the hole:
- 92mm from the seam between plastic number plate surround and aluminium boot lid cover.
- 400 mm from the right hand side boot lid cover edge (the seam between the lenses).
Schematic drawing:
On picture below notice the black 'T', which is the intersection of two black maker lines after the exact measurement:
Now drill the hole. You will have to drill through the plastic number plate surround and trough the aluminium boot lid cover.
In that particular area there is only one sheet of aluminium, which is about 1mm thick.
Through the hole you will see vertical metal rod (it will actually look like two metal rods sitting together side by side).
Insert a screwdriver so that it will sit to the left of the vertical rod and push the rod rightwards.
The boot will open.
You can then paint edges of the hole and insert rubber cover.
Here is the area after proper repair. Larger hole in the plastic surround to provide finger access to tightly sitting rubber cover.
I used rubber cover that lives on the inside edge of the boot lid cover (can be ordered from A8 Parts
):
If it'll happen again life will be much easier
Here is how the area looks like from the inside.
Edges of hole are painted and hole is sealed by rubber cover.
The vertical 'double rod' is the one that you push with screwdriver rightwards.
I know this last picture makes little sense, but after you remove internal boot trim everything will become bleeding obvious.
Good luck! Any questions -- shout.