A very small receiver ! It is a five autodyne consisting of a 'frequency changer', a two-stage IF amplification, a detector and the AF amplifier.  Autodyne simply means that an Autodyne oscillator, in a receiving device, generates the local oscillations required for beat reception [BFO] in addition to performing its other functions, such as amplification and/or detection; a clever valve/circuit for those days.

Its use [covered by a Confidential Book which we do not have] and its frequency range of 150 to 550 Mc/s, suggests that it belonged to the RCM Department [Radio Counter Measures - the EW of today] and because of its tiny size, in a covert rather than an overt role !

Anyway, here is a little file about the Receiver.

P33 RECEIVER.pdf