I picked up my used Mercian bicycle in September 2008 from a man in Seattle, Washington USA (where I now live).
The seller had purchased it as a frame/fork set which had been repainted sometime in the 80's by someone who apparently wanted their name written on the top tube which now reads "Eric Woodward" (see image: http://www.flickr.com/photos/andy_squirrel/2971412061/in/set-72157621890843753/).
Unfortunately, during the repaint the Serial number was lost (my guess, under a layer of paint) so I have no idea which model or year this was manufactured. The seller guessed sometime in the 70's.
I recently overhauled the entire bike and put more new modern components on it for light touring and rides around town.
Mercian on my first day of ownership: http://www.flickr.com/photos/andy_squirrel/2903470089/in/set-72157621890843753 (details about the purchase are in the comments)
Here is what the Mercian looked like before the overhaul: http://www.flickr.com/photos/2kings/sets/72157617217069615/
Here is an archive of all the photos i've captured for this bike: http://www.flickr.com/photos/andy_squirrel/sets/72157621890843753/
Seattle, WA USA