For those who study these things - and sometimes it unlocks a complete mystery - there is an alternative List of Service Numbers in the "Research & Books" section of this Forum. It doesn't go as far (in terms of time) as Wg Cdr Jim Routledge's List but it does show those numbers Never Issued. There are also a few differences, but as I'm Galley Slave tonight (we've got visitors) I haven't had time to compare both Lists in detail!
Happy Numerology!
Peter Davies