That's me in the top right corner (leading). Blimey, midweek "sick day" and I get some fantastic pictures from Joe and an indirect video, good times!
Coincidentally I don't know the route either, wasn't in the (far from extensive and obvs not a winter guide) Rockfax Western Grit. The route is to the right hand side of Downfall South Corner and follows a short thin section of ice (alternative to the r.h.s.) with poor placements to a snow scoop under a lovely little icefall and a slight overhang, some ice steps above. Ice all the way, no rock contact.
As to the grade: Definitely not a VI, maybe around IV? Was excellent fun, I'd thoroughly recommend it! Doesn't suffer from being blasted by the sun.
Might make a separate post on UKC later to find out if anyone knows the route...
Post edited at 16:01