Varitronic cdi unit

[thackers]

Can anyone point me in the direction of a substitute cdi unit for a varitronic ignition? Or which other motor they are used in? The chances are if they are a part for a modern machine they will be half the price that is asked for from a Lambretta dealer.
I think mines on the blink and don't know anyone who would be willing to loan theirs to test for the problem where I live.
Cheers