A forced landing on the side of a Scottish mountain should be very survivable. Landing on the upslope should mean your ground speed is very low - with fixed gear it will either tear off or spin or tumble the aircraft but with a bit of skill I'd be very disappointed not to get out of the wreckage in one piece. A lot of the time you can virtually hover of the peaks but it the wind in that strong then it may not ease sufficiently on the ground not to tumble you.
Of course surviving means having shelter and good clothing. That day was pretty nasty even on the coast, flying over the massif would have been horrid, the up and downdrafts alone would have caused real difficulties. I'll be interested to see at what height the wreck is.
The Norwegian who was rescued from his C150 when he flew it into the base of Mount Keen was nearly 1000' below the summit. He was so low that the slope was pretty mild and with doubtless a last minute pull-up the airframe wasn't badly damaged.
Forced landings in these areas are not about finding a decent field, they are about arriving at the crash with the minimum energy.