Well, after letting the London Mixture sit in a mason jar for a week, this morning I took out a bowl and let it dry for half an hour. I am smoking it with my coffee (a fresh ground breakfast blend) and am actually enjoying it quite a bit.
The first time I smoked it I think it was too moist and left my tongue feeling like a steamed ham, a bit of drying took care of this. Also, it has a delicate flavor profile that I wasn't able to pick up on last time, (in a lounge filled with strong cigar smoke) I believe the tin description of "soft and mellow flavour" is fitting. This is one I'm glad I revisited and will enjoy smoking more of.