Anyway, on a more serious note: I've hatched a plan.
The Dutch importer of JSB is going to see which batches they have in stock (new stock is expected in a matter of weeks).
They can then send me some samples, and once I can pick a batch that works for me (which will have to be verified with the blind test as I described earlier), I can then order a pile of tins from this batch to make me last some time.
I'll read up on Simon's "How To Miss" threads to see if I can come up with a testing procedure that I can actually apply.
Caveat: I just figured out that I have one tin left from the Daystate pellets that my AA SM/TM/NJR/PPH100 seems to prefer.