[Heatercathodeshort]

Completely agree with DC's information. It is tuned very slightly to the HF side.

You will have to ascertain which version of the fine tuning method you have. Early versions have a spring and plunger affair that was very nasty. If you have this version details can be posted but it sounds like you have the polythene tube.

A thin knitting needle with it's point shaped like a screwdriver tip will be fine but you have to take great care not to apply too much pressure and damage the oscillator coil.

If you encounter problems it might be better to remove the tuner side screen, remove the BBC [channel 1?] oscillator coil. locate the core and give it a tiny turn and test. If results are poor, return it to it's original position and again give a tiny turn in the opposite direction. When OK refit the screening can.

Murphy tuners are incredibly stable and do not require a customer adjustable fine tuner. Hope this sorts it out. J.
PS Try the charity shops for knitting needles, plastic of course!