There is another newspaper article which mentions the inquest on Gladys's death and says her father was James Whittle.
Elaine
It is always best to confirm information with certificates.

You know your grandparents were Lucy Hunt & Frank Whittle, we found their marriage in 1935 and it shows Frank as Frank W. Whittle. His death in 1969 giving his date of birth as 29th January 1913 leads to this birth registration -
Mar qtr 1913 - Frank W Whittle (mmn Read) - Nottingham reg district 7b 719
The period around 1911 is often a stumbling block. It is easy to search on freebmd after this time as births give mothers maiden surname on the index. Looking for a Whittle Read/Reed marriage gives two
possible results but the index does not show who marries who until 1911.
Marriage Dec qtr 1898
Gertrude Elizabeth REED
James Whittle
Nottingham 7b 491
or the one I posted earlier
December qtr 1900
Emily Louisa READ
Ernest Whittle
Nottingham reg dist 7b 596
Please note that Read is spelt differently.
You mention Franks sister Em, she could be the Emily Louisa bn 1910. She is not a daughter of James & Gertrude though. You would need to look at the 1911 census to see who her parents are.

I think you really need Franks birth certificate before assuming anything. These possible siblings posted earlier I believe have different parents as Frank is the only one shown as Read, the girls are Reed.
Frank b 1913
Edith A 1915
Gladys 1917
Rosie
