Hi David,
Many thanks for posting the circuit and the above comments. If another ECC82 needs to be employed to act as an inverter or anything else, that wouldn't be the end of the world. After all, I'm already fitting one for the black level clamp so two is not much extra effort!
As the set already uses a couple of solid state (I assume crystal?) diodes, if a 1N4148 or two were to find their way in there as well, I wouldn't tell anyone!
After all, these are reversible mods we are doing.
Cheers
Nick