Thanks for the good wishes.
Back at home now.
Arthroscopy done, detached minuscus now reattached, and all the loose bits washed out. Humungous bandage, and a bit of swelling, but the pain is not too bad.
Under instruction not to bend the knee more than 60 degrees for 10 days or so. Physio sessions booked in 2 weeks. Should be ok to start gentle spinning work then by all accounts, and back on the bike shortly after.
When it's healed up I'll then be scheduling opp no 2 to sort out the stretched ligaments which we are currently like old knicker elastic and not stabilising the knee at all. Hopefully that will be done next winter so I'll lose as little summer riding time as possible.