[Supersteve]

Hi Guys,
This might be constructive feedback, it might not, But I had the same issue on my F800S.
The bike was bone stock with about 18000km on when it started and we tried everything, eventually it turned out to be a fault on the fuel pump.
It was overheating due to being a faulty unit and only got hot enough to cut out if I spent alot of time on the bike, i.e. traffic and long trips and hot days.
Perhaps it could be something to consider, I don't know if the 1200 shares a similar pump.
I hope you get it sorted soon and carry on enjoying the bike.