This SCMP newsprint column tag 'Mammoth Ship' in the 29 April 1920 edition attracted my attention, but more interesting is that it was carrying 7,000 Czech troops when moored off Holt's Wharf. As a mid-European country with no obvious interest in the Far East what were they doing in the area? Shanghai interventions perhaps?
Date picture taken
29 Apr 1920
7,000 Czech troops
They were likely part of the Czech Legion being evacuated from Vladivostok.
Wikipedia has more about the Czech Legion, and the Siberian Intervention which they, and the Middlesex 25th, were part of.
photos etc here: http://www.simplonpc.co.uk/HAPAG2.html#anchor778527