May 2020 update: the medal is no longer available for sale. But I have left the details below for information..
By coincidence I heard the very same day that a gentleman had purchased at a German auction another, previously unknown, Gidley medal. He provided two photos. The medal commemorates not the well-known Bartholomew Gidley whose medal can be inspected in the British Museum, but his nephew and eventual heir, another Bartholomew Gidley. This Bartholomew is the 7 X great grandfather of Pete Gidley (above). Born in London in 1668/9, the son of John Gidley, a surgeon it is said to King William III, Bartholomew eventually moved to Winkleigh, and was buried there in the Gidley Chapel in 1702.
Jerome writes:
I recently picked this up in an auction in Germany. It was originally a medal commemorating the death of Charles II by the Roettiers, but the inscription on one side has been planed off and re-engraved to commemorate Bartholomew Gidley (1668 - 1702).
While I suspect my piece is probably unique, it has been mounted (in furniture?) and silvered in the past, as you can probably see from the photographs, and therefore in my opinion has limited value to the general collector, especially as practically perfect examples of the medal without the engraving come up from time to time at auction.