I've started this thread because it seems to be a different issue to one already posted, where the engine dies at low speed.
Just had the biggest scare of my life- going down a steep'ish hill, with a 90 degree bend at the bottom. Doing about 35mph in 4th gear. I started to change down to 3rd, and the engine died, with the loss of the power steering. Had it all on to navigate the bend and ended up on the grass verge.
I released the clutch in 3rd as it was slowing and it was dead. Once stationary i turned the ignition of, back on and it restarted normally, no warning lights, and didnt do it again on the way home.
It was pretty scary tbh. If the wife had been driving, it would have ended up in a ditch, without doubt. Will contact the dealer on Mon, but i am dreading the "no fault found" answer after a day wasted.