The mother's maiden name is only included in birth reg indexes from Sep 1911 so these with M.M.N. WALKER could be yours:
Dec 1911 Brown Albert O 10a 220
Dec 1913 BROWN Olive 10a 233
There are rather a lot of BROWN in Hartlepool before that, so the only way to eliminate some of those would be to wade through baptismal registers. Unless of course someone has a better idea?
Jan