Their first child, born 1909 in Lambeth, London,was also called Richard Deane Alder. There were also further children.
Maisie had a sister named Priscilla Gertrude Gough (b. 1883 in Ealing, London) who got married in Fylde, near Blackpool in 1907 (husband unknown) and a brother named Ernest John Gough (b. 1885 in Brentford, London) who married Gertrude Mary Lovell in 1910 in Stockwell, London.
I have some more information on the Gough line which I could share.