info in Reply 10 came from the GRO site.
www.gro.gov.uk - it is free to register and then search. If you wanted to purchase a certificate this is where you would do it. Births and Deaths come as PDFs by email, but Marriages have to be posted
Once I had those 3 births, I went looking for marriages at
www.Freebmd.org.uk Using the two surnames thus garnered, looking for one where the husband was A.H. Hawkins. Luckily none of the others had the same initials!
The baptism mentioned in reply #12 is on Ancestry as is one of the passenger lists. The other one is at FindMyPast.
the Navy lists are on Ancestry
Details of the sister found in the same way at GRO
Found her on the 1939 register and that gave her name change. Their parents can also be found on the register.
Using FreeBMD you can see some possible children of Jeanne, the sister born in the 1940s.
The Tatler piece is in the newspaper archive on FindMyPast, but you can also use the British Newspaper Archive
https://www.britishnewspaperarchive.co.uk and if you have never joined that before there are 3 free looks.
Hope that all makes sense.