Just for everyone's knowhow, I've worked out this problem.
e.g. <a href="http://www.address.com/Folder/Presentation.ppt#269,7">LinkTest</a>
the key to this is after the hash #269,7
269 denotes the SlideID and 7 denotes the SlideIndex
you will find these random numbers by opening your presentation into IE first and these will appear at the end.
Hope this will help some people