Cannot tell you anything about the rifle without pic's as Cantom already stated, but I can tell you that you have a rare scope, one that I have been on the hunt for a while.
There was about 8,000 Mk I scope's made with most likely less than 300 made by Vickers (UIC). Hopefully the scope has not been refinished or "beautified"; please post pictures if possible and if you ever want to sell.............drop me a note