The Green Man
Photo gn 010 is NOT Threadneedle Street.
That is the north-east corner of the junction of Holborn and Grays Inn Road.
There is no question - you can see the trolleybus wires emerging from Grays Inn Rd; trolleybuses were only grudgingly allowed near the City (the wires were deemed 'unsightly') and this turning loop was required for the terminating routes from North Finchley. Here and Moorgate were the only places in the actual City of London where wires were tolerated.
Confirmation can be had by reading the rather blurred legend above the descending stairs into the LT Station - look at the hazy words there and think:
'Chancery Lane Station'
..........I did, and squinted, and yes, well done Roger, superb deduction. Many thanks