Thanks to Vasili, who directed me to navaldesign's post on a single menu page with PHP in BV, I have been able to implement this neat trick on my website. See: >> Single Menu Page with Bv and PHP
However, when re-designing an existing page where this method has been used to import the header and footer etc, the text and graphics do no show in preview (Firefox, IE8, Opera or Chrome) - not even when online at time of preview. I have to publish the page to view changes.
Is there a way to see this data in preview? At present I have to continuously publish the pages to see what the overall look is - while in design stage.