Don't spend ages on it today if accessibility is poor. It might be better to wait for another forum member to advise.
This is because at the moment I can only offer you questions rather than answers. I'm wondering if there is a metering/loading issue when you measure the DC voltages. Otherwise I can't explain 13V at the cathode because this implies 1.3mA current here and the HT is only 100V.
If 85V was dropped across the anode resistance of 220k and 85V was dropped across the screen grid resistance of 150k this only provides 0.39mA + 0.57mA = 0.96mA total current going in via the HT.
I'm also a bit confused how there is 18V at the grid and 13V at the cathode. This means the Vgk is at +5V which seems highly unusual to me at least. Could this be another meter loading issue? One possibility for the strange DC readings is that the tube is preferring to go unstable and oscillate at a much higher frequency than your test gear can display although I think this is unlikely.
I did manage to find some data and curves for the equivalent EF73 valve in pdf format and I've uploaded them to here:
https://www.qsl.net/g/g0hzu//RF%20Tr...a/PDF/ef73.pdf
Maybe this will help someone advise better about the circuit. This datasheet does suggest that the valve can still generate a gm of 1mA/V even with just a few volts at the anode.