My god. I've heard people being quoted £400 to fix this Red Warning Message that stops you locking the car...
..shouldn't have slammed the bonnet so hard after filling up with screenwash. Took me a couple of hours to research this on the internet...
...and 30 seconds to fix.
LHS bonnet latch carries a microswitch that has to click when the bonnet closes.
The fix is to slacken two 10mm bolts and pull the passenger side latch assembly up a couple of mm.
And then tighten them.
Job done!