I can confirm (along with a squillion others I imagine) that what Tom says is true. The smoke escaped from the Lucas electricals under the dashboard of my brother's Hillman Hunter years ago and nothing worked after the smoke was gone.
I can also confirm that dry powder from a fire extinguisher is not suitable to replace the smoke as after a kg or so of powder was released under the dashboard still nothing worked.
Is it possible, I suppose, that Australian dry powder is not a suitable substitute for English dry powder which might well be a substitute for Lucas smoke?