Does anyone have any further information about this branch?
I have found this link to a West Ham Branch of the East London Federation of the Suffragettes (ELFS). Which split from the WSPU in 1914.
I found this fascinating quote here about East London in the First World War. "The worst outbursts of anti German feeling came after the sinking of the Lusitania in 1915. West Ham alone suffered £100,000 of damage after rioting. Suspected Germans were beaten up and their premises looted. The ELFS centres were used as refuges by those caught in the violence".
Update July 2013: I found this in the Museum of London website about banner "Suffrage banner of the WSPU, West Ham. Trumpeting angel design in central medallion adapted from Sylvia Pankhurst by Misses MA & E. Brice. The letters made by Miss Friedlaender and her brother, members of West Ham WSPU. Rectangular banner in grey green glazed cotton ground, purple and dark green velvet, pale green silk and wool and cream silk. Circular design of trumpeting angel in white silk with banner inscribed 'Freedom'. WSPU in cream silk against the bars of a prison cell window in purple on green velvet. 'West Ham; on either side at the top and 'Courage Constancy Success' along the bottom, in letters of white silk stretched over a cardboard core.