Magneto Condenser

[A G Wood]

Very useful.
The Magneto Guys site tells me a capacitor model, make, capacitance range and how to fit one. Very handy. Useful that I have another incomplete spare ML magneto to examine before burrowing into the one under suspicion. 

Time to order a few capacitors then

Yes, Charles.
They're surprisingly (at least to me) informative about their techniques which must've taken lots of time and effort to develop into a replicable and permanent repair method.
Generally, specialised repair outfits (in my experience) are very secretive about their proprietary stuff  Intellectual Property (IP)