Thanks both for your replies, I have found her in the 1911 census under the name of Florence Cook, with her sister then called Louise (they had dropped the Lilian) with her mother Florence Cook and stepfather Thomas Cook, they were boarders at 18 Abbey Road Barking!!
What do you think this address was? There are a lot of boarders so presumably it was some kind of lodging house.
I will post a queery and see if anyone knows what sort of place it might have been
Thanks again - what a tangled web!!