Well, I've taken the blood sample (needed two needles as the first finger stopped bleeding) and sent it off to the lab via Special Delivery.
The bad news is that it wasn't a 5ml tube, it was a 10ml one... and you had to fill it up. Messy, as I've not done anything like it before, but not especially painful - two small pricks and a slight throbbing afterwards.
Meanwhile the village - Leysdown - was the busiest it's been in weeks, with queues outside the bakery and general stores. The post office was fine, though, and after seeing the alarm on the postmistress' face I mentioned it was an antibody test, not a "have I got it now" test. (Having a big purple "covid-19 test" label on the enevelope wasn't a great idea, unless it's meant to ensure it speeds through the system faster).
Assuming it's a viable sample, I should have the results on Thursday. I'll post them here when I get them.