I’m currently mucking around with some PL82 valves strapped as triodes. Both are NOS UK made Mullards but they are quite different in their performance. With exactly the same setup one draws around 20mA and the other draws only 16mA.

Has anyone else seen such a variation with old TV or radio valves that were not made especially for high fidelity audio?

The currents mentioned are quite low for this type of valves but I am not sure that would really matter.