Thanks Paul for the info on the 1945 excavations.
1930s was an approx. guess on the picture I posted of the excavations in Snargate Street, these are probably the same ones Paul mentiioned with the link to the Flicker page, it is quite likely the excavations were immediately post-war during the clearance work taking place.
another of Snargate print from a print in Batcheller's Guide 1874: