Well shit a brick!
I hooked up the Flasher Can to an Ignition Coil (out of the magneto off a old Briggs and Strugglin I had lying around!) and wired it to my Power Supply, and what do you know, a nice steady click,click,click, just like when you flick on your Indicator on you Car!
It throws a fair spark (a little on the orangey side) but certainly good enough to light an L.P.G. flame!
The poor quality of the spark is (I suspect) probably due to either;
no capacitor on the relay in the Flasher Can or,
that it is totally the Wrong coil or,
a combination of both!
I'll rectify that by getting a proper G.T. 40 R Coil (they actually run on 8 Volts and only require 12 Volts when starting) .
The upshot is I may be able to run it off a 9 volt battery to keep it all compact!
(it draws a fair bit of current cos the relay spends most of the time in the normally closed position i.e. dead short! So if it runs on a 9 volt battery it's already current limited!)
And of course, put a capacitor across the relay points in the Flasher Can!
Well that's it!
First update complete.