John Stanley Stringer was in the newspapers on several occasions

He and Ethel broke up?
Luton area
In the mid sixties, up to 1968, there was a John S Stringer at 80 Caravan Site, Woodside, The Grove, Caddington.
Living with Rosa Stringer
Rosa Stringer was on her own at the caravan site on the 1969 electoral register.
So it looks like it's him.
Possible marriage, March 1963, Barnet 5a 1639
John S Stringer + Rosa Magnante