Long plate, square getter, Factory code mC1 B5J, which I think confirms it was manufactured at the Blackburn factory in October 1955. Tested on an AVO CT160 before being put into storage some years ago. The two sections tested at 1.5 and 1.3 mA/V respectively, so a good strong result. Incidentally, the test results written on the valve are in black felt pen and will simply wipe off with alcohol.
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