Hi Paul,
Many thanks for the explanation, but the figures in this particular case weren’t adding up. I believe there is much more than the just the header and footer height to consider. Referring to the image, to set the correct minimum height for the inner container (red) I’ve had to account for not only the header & footer (blue), but also the title area (purple) and the offset values (yellow) - finally there’s also the margin (not shown) above the title area.

For others reading this thread, with so many factors to consider, I found it much easier to simply adjust the pixel value in the inspector until I got it right.
I think it must have been the margin and/or offset values that were throwing out RueNel’s original solution.
Thanks for getting me on the right track
Great support !