[Tobias]

Ken. Thanks for that. yes - the instructions say almost word for word what you suggest below, so it must be that the start point (fully wound in) is the minimum vacuum advance setting.

I'm going to try setting the initial advance to 15º this week (it's at 8º at the moment) and then play with the adjustable vacuum advance.

Will post here to let you know how I got on. Once again, thanks.