I completely understand the general point here.
The only thing I'm still not clear about is shown on your circuit diagrams: -
Attachment 3, the coil goes to zero V via the Zener(s). On Attach 2, it goes to "OUT". Is "OUT" 0 V ?
In my actual circuit, which works fine but maybe discharges too slowly - the whole point of this (very welcome) discussion - my circuit has the "bottom" of the coil going straight to 0 V, but there is a bypass back to the "top", via the diode.
In other words, it would be just like your Attach 3 if the diode was substituted for the Zener.
So if I have the diode feeding back (which I have), but a clear run from the "bottom" of the coil to 0 V, is there still a slow discharge????