Telephone; station to station in steel case with hinged door from District Line station, circa 1980

Telephone handset in dark grey steel case. Outer case has two labels. One self adhesive with yellow lettering on a green background reading 'Station to Station Telephone' and the other with blue enamel background and white lettering also reading 'Station to Station Telephone' . This latter also has another self adhesive label on top reading 'Not in use'.
Written in black felt marker are 'Sloane (with square symbol)' beside switch 'Sometimes cradle sticks a slight oil to free it' and 'Lewave line switch in mid position when end call' on inside of lid.