Hi Grumpy,
I have found a guy over the north shore of Auckland who has one just waiting for a price (2nd hand)i asked him for a new lead as well just in case.

as for the kill wire I did disconnect completely it a week or so ago it didn't make any difference.
so it kinda looks like the coil is dying and your right you have a good memory i did report that the spark was on one minute off the next.
Pete