Thanks for the link.
The scope I have does not have a removeable end section to hold the front lens - only the threaded lens retaining ring inside the scope outer case, so I am guessing this will make it a whole lot harder to adjust as some form or spacer will also have to be inserted behind the lens.
I will take a look and see how practical it wil be to do this. Maybe I have the wrong scope and it would be better to sell it or exchange it for something more suited or more easilly corrected for 10 metre use?