I was not aware of a Lionel Baker as a brother of Roy Baker. His mother's name was Rebecca Elizabeth so t is a definite possibility and I'll be looking into that. She did have a son in 1912 (out of wedlock) that died.
I doubt very much that it was Roy in 1933 and 1934 in the school concert and the Sunday school concert as he would have been 16/17 years old then and no longer going to school. They did however at some time live in Byron Bay also.