Ok I seemed to have solved the problem. The desktop sharing utility is included in the Kde network package. the version I was using was quite old. I eventually managed to install the latest 3.2.2 version after doing a --nodeps. This was because of Ksirc dependancies that I could not satisfy!
I now have more options supplied in the desktop sharing utility namely the ability to allow a remote connection without having to authorize it at the host machine

Now if the host machine is running X I can use realvnc on my windows machine to connect it and navigate around the desktop as though I was sat at the machine.
I'm happy now
