Thanks Ralf and Tim.
Tim - I've attached the file in TC V21 format, and added a few comments to the custom code, some of it is just restricting movement as the first time I did it, the flame ended up outside the glass dome
The code just randomly manipulate four of the six circles used for the compound profile of a loft, and alters the intensity of a luminance (assigned to the wick) between two values, one of the circles also has an x/2 just to give some extra variation.
Ignore the 'slashes' in the code - I just usually put them in any code so I can easily see where the notes are, the only odd thing is the light on the wall, which isn't really supposed to look like a circular pattern, it's just the way AnimationLab produced the AVI, and I didn't bother trying to find out why.
Don't laugh too loud at my flame wrapping image (attached). I decided it didn't need to be accurate, just needed a separation between blue lower area and yellow/white upper.