All in Yasni Exposé of Lucy Johnson

I am the middle daughter of Horst Wallbaum, born in Hamburg, Germany. He was born in 1930, the 18th of May. He has passed away in the last few years but I am desperately looking for any of his family. I know nothing other than I believe his Father's name was Ruhdolf Wallbaum, and when my Dad emigrated to Australia, he changed his name to Errol Byron. My Dad once said to me that I looked like his sister. That is the only thing he has said to me regarding his family. I would love to know more. I only speak English, unfortunately