Keith, your grandfather’s siblings point the way to further findings. From September 1911 onwards the births indexes include the maiden name of the child’s mother. The names that you give all have the mother’s maiden name Flood. They are as follows, including the three youngest that died in infancy:
William 3/1912 West Derby 8b 448
Joseph H 12/1912 West Derby 8b 207 [died 6/1976]
Edward F 12/1914 West Derby 8b 428 [died 3/1969]
Herbert H 12/1916 West Derby 8b 389 [died 1988]
Harold E 9/1918 West Derby 8b 360 [died 9/1919]
George F 3/1920 West Derby 8b 591 [died 9/1922]
Edith M 3/1923 West Derby 8b 574 [died 6/1925]

If we look for May there is one that fits:
Florence May 6/1910 West Derby 8b 238 [died 6/1962]

Thus your father named the siblings in exact order, youngest to eldest.

Letters of administration were granted to the estate of Florence May Joughin of 68 St. John’s Road, Bootle, Liverpool 20, who died 1962 June 24th , by the Liverpool Probate Registry 1962 August 20th to Mary Elizabeth Cragg, widow. There is that Cragg name that you mentioned. So FMJ dies a spinster and her mother inherits. Now we know we are looking for a marriage for Mary Elizabeth Joughin, and here it is:
Joughin, Mary E to Cragg, James 6/1929 West Derby 8b 963

If you go back to that 1908 marriage of Charles Joughin that I mentioned in my last posting, you should be able to find, in the marriages index for March 1908,
Flood, Mary E West Derby 8b 328.
If you do, you know you have got the right marriage, and it should give you (we hope) his age, and his father’s name among other details.

Here’s something else, among the marriages:
Joughin, Herbert H 12/1937 Crosby 8b 1154. Bride’s name: Martha G Cragg!
Could that be his step-sister? They had a son who went on to marry and have children. I have stopped giving details as we are getting rather close to the present, but if you want further information, perhaps with a view to contacting your relatives to see if they know anything more, let me know. Perhaps we ought then to switch to e-mail.

Philip Allen