In January 2000, because it was cheap that time of year, I did my PADI Advanced Open Water Diver at Stoney Cove in Liecestershire. Its was snowing a bit when we arrived and I think the water temperature was about 4 degrees.
We did a 30 meter dive to an upturned Watertank on stilts which is pitch black and there have been a number of fatal accidents there. That kept your mind off the numbing cold for a while. Ascended and did a safety stop on the way which just plain hurt with cold.
Surfaced with blue lips and when I got out wanted to pee but there was a slight logistical problem with that. Lets just say no man would venture to the Northern End of Arillas beach whilst that cold.
Thank goodness for chemical handwarmers.
Did my drysuit specialisation later that day which was a lot better but have never dived in the UK since.
May in Arillas, no problem. Bring a shorty wetsuit for a longer....erm... session.