Hi Andy,
TSE4 secondary emission valves have a very high mutual conductance figure, 15mA/V, same as the EF184 frame grid valve.
However, but it's not just the gm, also important is the input resistance at VHF.
The T5 employs conventional RF pentodes in the receiver unit. Safe to suggest that the TSP4 is a rebased Philips 4673.
https://www.radiomuseum.org/tubes/tube_4673.html
DFWB.