Help with Maternal Grand Father William Parfitt Wales

I don't have much to go on as my mother and grandmother are no longer with us.
I know my grand father was around 16 years older than my grandmother and she was born in 1920 I think may 16th in Guildford Surrey. Her mother was Emily and my Nan was illigiitimate her name was marguerite. I don't know her surname. But her mother later married a man whose surname was hemsley and they had 3 sons together I think
My grandfather was from wales and that is All I really know. And that he had brothers. Not much to go on I know.