I have for sale my Malcolm Style 6 X rifle-scope. It was side mounted on my Henry 1860 lever action 44-40. These were designed to fit onto Winchester's early lever action and reproduction rifles. I mounted this one using and additional dovetail cut into the barrel. This would not be required on the Winchester. There are two sets of mounts that come with the scope, for either side mounting or top mounting depending on the position of the ejection port on the rifle.
I had this imported from the US but they are available from some suppliers in the UK at a cost. I want £220 for this one plus any postage cost. If you are interested PM me via this site.