Hey, thanks for the quick reply... The form was built from scratch using office infopath 2007, but based on an old word form.
Not sure how much build detail you want but its a fairly standard layout, using tables for tidiness, a number of check box controls etc etc.
It was first published to out sharepoint site for local use only but then became a group wide document. When I open the file through sharepoint i see the form as it should be without any editable options except the text boxes and check boxes. I select the 'mail to recipient' option from the top menu, outlook opens a new mail box and i see the form perfectly, just as it should be. However the recipients see an altered form and the xml attachment.
I have also tried the publish to email option in deisgn view with the same result except with the addition of an xns file.