Eventually I elected not to use this method - it would have been helpful if there was a definable layout part which was used as the 'filler' which sat between the trailing grand summary and the footer - never mind.
I decided to use a portal to display the records, I would filter the portal records depending on which page of the report I was 'on'.
Using a Portal allowed total freedom on the design of the rest of the page - job done!
This is a known limitation of FileMaker Reporting. The latest versions (12, 13) have added new ways to insert background graphics via the appearance tab. These are supposed to be a way to add graphics as borders to the layout so you might explore those options in FileMaker help to see if you can get that to work for you. (And let us know if that doesn't work for this particular issue.)
Thank you for that. I have been working in Filemaker 11 though for this project the user will be using Filemaker 13. I just took a quick look and can see that it is very easy to set a background image to an object and/or an entire layout. I can see that this would help achieve the effect that I was after though having now gone down the route of using a portal view and filtering records depending on which page of the report I want to display I can already see that I would be able to apply more flexibility using the portal based method - ie. different 'first' or 'last' pages etc.
Thank you for your quick response.