bokeSimilar experience in the US. Ebay has a few 6AD10. The lack of availability has kept me from getting this amp. I went for the Mini2013 instead mostly because those tubes are plentiful.
bokeThe 6AD10's are out there, but usually come in singles. It should be okay if you go for NOS singles of the same manufacturer. I, too, saw them on ebay and at a few dealers such as tube depot and the tube store. The dealers probably have enough in stock to sell pairs of NOS tubes of the same make and measure similarly.