Just in case you're not doing this: Draw a square (placeholder) place this square where you want your form to be. Right click the square > web properties> placeholder> HTML code (body)> and paste the code from jotform (Iframe) into this box and click apply. Now your form is embedded into this box (placeholder) and you should be able to move it anywhere you want. Click "export and preview page" to see the form on the page.
It worked!! and without a single error message Thanks Camelot.

Resizing the placeholder did influence the size of the form though, not in length but in width. The form appears in preview the same width as my placeholder (a black rectangle) but the length shows the entire form (though my placeholder is only say 30 px high). If I make my placeholder narrower then half the width of the form is missing but it's still on there in length. Strange!

Thanks so much for your advice always pays to ask!!