Just spotted this on my way in to work through the snow. Looks like it was at all Morrison's filling stations (possibly replicated in-store too?) - the one I visited was on A62 Oldham Road on outskirts of Manchester. At least 40-odd containers on display.
Looks like a good deal to me - filling stations aren't usually the best places to get cheap screenwash, but this was a) under half their usual price and b) cheap anyway. Works to minus 5 degrees C (it claims). 5 litre container.
First deal posted - shame it's not summat a bit more exciting. Let's be careful out there!