I used to have one of these receivers when I was a youth ( >40 years ago), I checked today in the cellar of my mums house where it was last seen to see if by any chance it was still lurking but unfortunately not :/ Back then (mid 70's) I used it as a tunable IF fed from the output of a TV UHF tuner to listen on the 70cm amateur band, which worked a treat. I remember that as purchased it had a fault where the local oscillator 'squegged' at several kHz and I cured it by placing a resistor in the grid lead of the valve.
The box with the multiway connector on top on the front panel had a cover with a tuning fixture consisting of a dial marked 30 to 40 Mc/s (or thereabouts) and a local control knob, but also an attachment for a flexible drive that would have allowed remote tuning from the pilot's or W/Ops position.
Best of luck with this project
Alan