Ariel Owners Motorcycle Club

Have just bought Champion D9 spark plug - but the current plug cap (LB05EH) doesn't fit as the spark plug is wider than the old one.
I could use a spade end fitting but would like to know if there's a plug cap that fits?

The plug is missing it's screw-on terminal!

answered my own question:

None of the NGK plugs caps fit the Champion D9’s.

But these do:
Pattern Spark Plug Cap R90 Black Water Resistant Rubber Lodge No Resistor
https://www.gsparkplug.com/1x-pattern-s ... istor.html