Mike, your map shows the island with what looks like the tram track going through the middle. 1962 was a long time after the trams stopped running wasn't it? So what is the dotted line? Hadn't the island gone by then too I wonder? I'm sure someone will know.
Slightly off topic but many years ago the trunion pin of one of the wheels of my Morris Minor snapped off and the wheel came free, making it's way down the Chester Road without me. It was rush hour on a Friday night and the road now narrows to one lane exactly where it happened. Right about where the middle tree on the left of the map is shown. I learned a few new words that night - no patience, some people!