Note. Laurence Worms at Ash Rare Books - http://www.ashrare.com/laurence_worms.html - has kindly supplied the illustrations of Fred's 'very interesting' map, along with this note.
'This sounds to me like The Directional Pointer Guide-Map to Wimbledon, first published by E. J. Burrow & Co. of Cheltenham & London in 1931. They are a species of what are known as ‘tape-indicator’ maps, which first surfaced in the mid- nineteenth century. You simply swing the marked-up tape across the map to read off your destination from the key in the margin.
'Burrow & Co. made similar maps of towns all across the country. The British Library has five separate editions of the Wimbledon map up to 1939, but the attached pictures are apparently of a ninth edition as late as 1961.
'I think in fact that the ‘ninth edition’ of the pictures dates from 1956 rather than 1961 – there was a tenth edition in 1958, an eleventh in 1960 – and a twelfth in 1964.'