Thanks for your reply JPmiaou
I have no firm information as to their Religion
But suspect it was Catholic
The birth date of 1863 was an estimate so 1861 is plausible
The maiden name of Gagerhofer I found on a British Gov document from 1936
But a unverified source lists the name as Jagerhofer?
This Special Branch document also states that they have sighted Alois Eckert's original birth certificate and confirm the surnames on it are spelt ECKERT
The one thing I know with absolute certainty is they lived in Vienna