Thanks for that, aghadowey - I hadn't noticed that I was in the wrong section!
Topic moved.The child involved was Kathleen Semple, born 24 April 1906 at 3 Maryville Street, Belfast (I have entry) Her father was John Semple of 9 Auburn Street, Belfast, her mother was Eliza Semple, formerly Morrow, who signed the register, and gave her address as 3 Maryville Street.
John Semple and Lizzie (sic) Morrow had married at St Anne's, Belfast on 6 February 1900. John's address was 9 Auburn Street as above (the Semple family home) Lizzie's address was her parents' home at 39 Roden Street.
In the 1901 census, the young couple were living at 11, Conduit Street, with their 7 month old son John.
By the time of the 1911 census, John Semple was back at 9 Auburn Street, with his widowed mother, several siblings, his son John + two other children who may or may not have been his - Florence May (7) and Norman Richard (5) So far, no sign has been found of either Eliza/Lizzie under Semple or Morrow, nor of Kathleen who would have been aged 5. No obvious sign in Scotland, either, although Kathleen ended up there in later life. No death found for Eliza at relevant period.
Possibilities including death of Eliza, and Kathleen living with other family members but why were parents' addresses different on her birth entry? - possible separation, or what
Any help gratefully received!