"Colin Youngs" wrote :

Have there been (many) other cases so far this winter of min. temps
below -10°C ?

20th Nov -13.2ºC at Kinbrace (Sutherland), 20th Dec -15.2ºC
also at Kinbrace. The lowest in January that I'm aware of was
-9.2ºC. These were just the lowest in each month.

Interestingly, several recent years produced notably low
minima at the fag-end of February / beginning of March,
in some cases the lowest of the season ... 2004, 2001,
2000, 1998, 1995, 1993.

Philip Eden