[Neil Purling]

Not much mystery regarding the 'guts' of this set. A 3 valve TRF with a metal rectifier.
The earlier ones used military surplus components. The fact you have had a 'tickle' from the aerial wire is alarming. Normally there should be a coupling capacitor between the serial coil & the wire aerial. This should be a low value mica capacitor. Those should not fail, but any other kind that are present ought to be regarded as suspect. Any waxed paper capacitor ought to be replaced without any prior notion of testing them. There is one location where a leaky capacitor can wreak havoc. It is the coupling capacitor to the first grid of the audio output valve. It is referred to as "That Capacitor". So notorious is it that it ought to be the first component to be changed.
Alright.. I know I am drifitng off topic. Our new friend needs to know these things.

Normally the tuning ought to be driven by a cord between a shaft & a far larger pulley attached to the tuning capacitor to give a reduction. Why the convenient reduction drive was dispensed with puzzles me. Maybe it just wasn't necessary with far fewer stations on the air then?
What are the valve types?
If that metal rectifier dies it will whiff like a old-fashioned privvy. The HT should be around 200V, as it is derived from the mains & the voltage drop across the rectifier is around 50V.
the rest of the Forum can advise on choosing a diode & resistor combo to keep the HT voltage from rising too high.
The audio distortion could be down to the leaky grid-coupler capacitor. Find it & change it!