Thanks again Gadge!
I obtained an old nut, a little worn from the mower shop and the owner kindly loaned me a 1/2" BSF tap to run through and clean the thread a little (though it's somewhat loose). I'm going to call in at my local bearing and bolts centre today and see if he has a bolt and might obtain a couple of standard nuts and weld them together, then run the tap through to repair the shrinkage from welding (I'll put them together on a bolt to align the thread and tack them). That should give me an equivalent height stand off nut.
Any ideas on the electronic ignition module or does that question belong in another sub forum?
