It is with great delight that I can report my missing spark has been found. The HT lead on the left side had a flat metal plate soldered to it. The HT lead on the right side, presumably had a flat metal plate attached to it many years ago, but it looks like it was undergoing a trial separation. After a brief search inside what I am going to call the distributor, but I suspect it probably has a different name, the plate was located. Thus removed and after a lot of cleaning and sanding, followed by a couple of blobs of solder I have two lots of sparks and some matching noise…..