I have now found the original births for Frederick, Eva and Stanley. It appears that their parents died in 1925 and 1928 so hence the reason for the adoption. Fortunately I have been able to find them as they kept their original names from birth. Frederick was born 1917, Eva 1919 and Stanley - which we already knew was 1921. Their name was Cooke. If anyone knows any details of this family please get in touch.
I am still looking for the other information that is listed in my previous post. Still no luck on any of that.
Thanks