Hi Buachaille,
I hate it when people don't write the solutions to their problems on forums, turns out that I am now one of those people!! Ooopps, sorry!
Firstly, what you tried did nothing for me, I tried any and all combinations of turning on accessories (like cameras, lane sensors, cruise control, etc..), tried manual, even tried crazy things like turning the car off (attempting to) while it was in 'drive' to attempt to reset/jolt the computer, nothing...
So, I took the car and they told me that it was an "environmental sensor" that was causing the problem. All replaced under the warranty of the car, and the car has been working fine since then.
The problem is (as always), I am not a 'car person', so I am unsure if this is 100% the truth or not. I have since purchased one of the many OBDii car scanners on the market, so if a fault like this occurs again I will not be blindly trusting someone else.