elvee,
Thanks for that mate. I actually tried that solution before I posted and while it works you get that Windows message 'This file may be harmful to your computer blah blah blah' and then the Dialogue boxes 'Save', 'Open', 'Cancel' etc. Unfortunately you cannot force it to open it by changing the 'Always perform this action' checkbox as it's greyed out and inaccessible.
Does anyone know how to force Windows to open a particular file type without giving this warning?
Otherwise the solution works but it's not elegant >