pearce family uk

I'm trying to assist a friend with her family tree (without much success)the info we have is below.
Frances (Fanny) Pearce b 1863 Portsmouth Hampshire (according to 1901/1911 census) Mother Emily A b 1838 Kingston London (living with Fanny 1901) father Walter Pearce (only found on Fanny's marriage cert)
Frances married Sydney G Foster (sometimes Forster)1889 St Georges Hanover Square London Had one son Frank Leonard.
Unable to trace marriage for Walter and Emily or birth record for Frances.
Any info gratefully received.
peter