Sorry,
@Brunneria - when talking about last meal effect, I usually just whitter on descriptively. (Others would cacll it waffling on!) Ahem.
One other thing I would wonder about
@dogslife is whether any of the ingredients in your lunch changed at all? I'm thinking simple things like gravy mix or thickeners, which can be a bit rogue, if you happen to be a bit sensitive to something in them.
That 12.1 seems uncomfortably high, but I think it would likely be very helpful if you could find the few minutes to test a few times more - whether or not you have hypo symptoms, dogslife. In this weather, if you have been bustling around, very busy, as you describe, that you don't drink enough in the run up to and throughout the lunch club. Dehydration (on of my personal hobby horses, I'm afraid!), can lead to higher blood sugar readings, but can also lead to some horrid symptoms in itself. By the time we feel thirst, we're often a bit dehydrated, so are already playing catch up.
Those are just my thoughts.