Just been checking, Elizabeth is married on the 1911, and married in 1902, so the baptism I found on familysearch is not mine.
I have just bought the birth pdf, the mother is Agnes and she is with the family on 1911, but no Dorothy May. I'm not subscribed to ancestry/FindMyPast so can't search fully, but Dorothy is not proving easy to find. How far away would she realistically be?