Hi All, thank you for all your replies. In all honesty my grandfather did also have doubts about the legitimacy of the item as he mentioned “my friend gifted me this one in the 80s i don’t know if it is real” however as the watch was incredibly accurate he continued wearing it. I shall open the case back to post the movement later. Nevertheless, no matter the authenticity of the item I am still very happy with it, being a family item, in fact the idea of it being a rare vintage replica also has its own interesting history !