An excellent way to get an aerial view of where the allotment sites are and how they look is to go to http://local.live.com/ and put in the postcode of the nearest road to the site or just the road name from the list of sites in this section with the map icon.
You can then zoom in almost as close to see the crops !
Map of Allotment sites and locations
See the overall map and locations as numbered on the allotment details