It would help to see the drive side of the bike, as well as a few more frame detail pictures. That said, I have owned several Falcon bicycles and you might glean a bit of useful information should you take a look at that article on MY "TEN SPEEDS".

As for vintage, early to med seventies probably and more than likely a Falcon Black Diamond. The model with the Reynold 531 tubes generally has a wrap around seat stay set.

Hope this is a help.