Richard,
Are you sure it was a
super-regen? I've only seen a handful of these for MW reception (OC44 wouldn't really get you into the realms of SW). I can remember one by Sir Douglas Hall in the Radio Constructor (which used far too many now unobtainable Repanco TT53 microphone +other transformers!); the other was either in the PW or RC (again) using a surface barrier transistor - I think written by someone living in the W. Indies.
One of the issues about MW super-regens is getting a low enough quench frequency to achieve reasonable super-regen gain (which is related to the RF:quench freq. ratio), whilst not being left with an audible whistle at quench frequency. Indeed, the Sir D.H. circuit was followed up with a suggested audio freq filter to put in the audio output stage. (I think the q. freq was about 10kc/s).
HTH
Dave