Further unexpected overnight snow in Southampton, and it was snowing
when I got up (stopped around 0830). -9.7C in Dorset? That must be a
close on record low for this area!

It was certainly cold. My machine at work recorded -9.2 twelve minutes
later at 0513

It has since risen smartly to 2.1 but has slipped back to 1.1 - there
is a drift off the Channel so maybe

R