John, It's possible to pick up traces of this family, but so far they have not really led me anywhere. Michael's siblings were Ivan Edmond/Edmund Holmes and Hazel Hilda Holmes. They were the children of Edwin Alfred Holmes and Ethel Maud Caroline Powlesland, who were both born in India and who married in India in 1899. I have not found any other children. Hazel Hilda was born 25 Sep 1900. Ivan Edmund was born 5 Oct 1902. I have not found anything more on Hazel, but Michael (born 21 Jun 1910) and Ivan came to England in Jun 1948 - Michael described as a School Master and Ivan as a Railwayman. Neither were accompanied by a spouse. There are matching deaths for the Worthing Registration District. Michael in March 1998 and Ivan in April 1998. There's a marriage for an Ivan E. Holmes to a Mary B. McMahon in Worthing in 1979. If it were me I would direct my searches to the Worthing area. If Michael remained in teaching then he might rate a mention in the local newspapers. Similarly there might be an obituary for one or both of them. The certificate might be useful, if only for confirmation (or otherwise) that it was for the "right" Ivan. The birth index does not indicate any children (not surprisingly if it really was Ivan!).