yer not gonna believe this but....
I just won a pair of lace up boots with mid-heels off ebay, same brand as the other rattler and... ...yes... ...same right boot/shoe too... ...another rattler and worse too!!!
well this time I wasn't gonna be beaten and I got both rattlers out together, fetched the putty knife and broad chisel and sorted them out.
the putty knife was good for an initial probe and feel for the pegs and pins and create a first crack then the heavier chisel opened the cap/lift off from the breast side. I angled the bevel of the chisel so all the pressure was on the cap and so no hint of damage could possibly be done to the heel.
the offending foreigners soon popped out, a bit of plastic swarf in the old shoe and something bigger which bounced off somewhere in the new one.
no damage done to the pegs so the lifts snapped back on, and if they move later a drop of glue will deal with that.
this closes the story for me, hopefully without recurrence!
hope this helps anyone else who gets this nuisance.