Liz Re . your first question Richard P Crennell is at 26 Barrack Street Douglas [ no longer there ]
He is shown as Head etc. but might not have
been married legally to Myra J . born Jurby & therefore Catherine registered in her mother's name.
OR there may be omissions from Brian's list. Look
for Catherine as Crennell at BMD I am sure she was registered officially at that date. If you can't
find her pay £3 to look at appropriate ledger . Start
at page I & look for a girl with mother Myra[ a nice unusual name. ] & hopefully find your surname.