worn rear dropout and bad wheel alignment

First thought from the glimpse of the fancy lugged headtube was it might be an old Carlton.

Seatpost size can sometimes help indicate tubesets, although 531 stamped into the tube is good clue :)

http://www.hilarystone.com is worth looking at, you might see something similar and he does do a lot of links to various brands history.

Butchering chain tugs is proberly a good bet unless you have a magic pot in the shed full of assorted washers and axle spacers.