What a coincidence, I also grew up with AM radio receivers in their simplest forms !
I remember my Science fair kit 150in1 kit with it’s Germanium transistors and simple crystal and reflex receivers.
Later on, I used FET transistors and HF circuitry, followed by heterodyne receivers (Philips EE 2000 kit).
Still now, I love to listen to AM radio sometimes, only receiving very distant stations, like UK, Italian, Spanish etc.
I haven’t build AM radios with the Lectron set yet, I do have the AM receiver block (ZN414) and will try it for sure.
Your circuit seems very cool, a mixture of the first stage of a heterodyne receiver with LF feedback.
Did you use a printed circuit board or did you just made a wired cube ?
The oscillator and IF coils, are these from a normal AM radio ?
I will try to replicate your circuit (on a breadboard).
Keep on posting those receivers ! I admire your skills in building customized blocks !