OK, some further research:
I emailed the supplier and now have confirmation that the Hakka LT2 is illegal in UK and France, so that's a complete deadend.
So in 235/85R16 that leaves the Kumho CW51s, the Kumho CW51s or the Kumho CW51s.
I've toyed with the idea of going down to the 235/70R16: then the choice widens substantially and I could get the Blizzaks, but friends advise against using the smaller tyre (gearing changes, speedo overreads).
So I'm now looking into chains or other traction aids to augment the Kumhos when it's really deep/slippy.
rrocket, have you used the flextrax snoclaws yourself? There are quite a few wildly enthusiastic reviews out there, but a lot of them seem to be linked to the inventor/supplier in some way. It's harder to find stuff that looks both positive and independent.
I don't rule out the snoclaws and am continuing to research.
On the more traditional chains front, I'm planning for chains on all four tyres. That rules out some of the absolutely top spec chains (ie, Spider Spikes) on cost. At the top of my list at the moment are the Thule/Konig XG12 (look fiddly to fit, but seem to be high quality product) and the Pewag SNOX SXV (look supereasy to fit, almost like magic, but are they robust enough?).