Dear Len,
Yes, as you say, Lucas did make ignition devices. Sadly like much of the British motor related industry it is either owned by an overseas company, doesn't exist any more and certainly doesn't make equipment that was deemed obsolete over half a century ago.
We are fortunate to have several ignition options available to Vincent Owners who still want to ride their bikes. If they want independence from a battery\charging system they can have a failing Lucas instrument rebuilt by one of many people offering this service or they can fit a modern electronically controlled BT-H magneto. If they have a good charging system there are Boyer based systems, Pazon, Francois Grosset's system, "D" type points systems if they can find the bits and probably many more to choose from. "You pays your money and takes your chance. " No sarcasm implied or intended.
Forgive the sarcasm but didn't Lucas used to make an Ignition device that avoided all that trouble? Shame they still don't.