I'm now considering KB4058258 (OS Build 16299.214), apparently MS say:-
“Resolves the issue reported by some customers on a small subset of older AMD processors where the processor entered an unbootable state after installing January 3, 2018—KB4056892 (OS Build 16299.192
How do I install .214 on a PC that entered an unbootable state after KB4056892!!**!!