Thanks David.

Your answer cured the changing size problem, but unfortunately the images do not hold the same position within the graphic frame when they are updated – they are graphic icons at the end of heading lozenges and so due to the shift in position the whole graphic is not showing. Do you know how to cure this too? I'm going to have to Package each book as a get-around, but I wouldn't want to keep doing this in future on other projects.

Cheers