Surname alteration in 1939 Census Record?

[edmin01]

I have just noticed that my mother's family surname has been crossed-out in the 1939 Census and her, later, married surname written above instead. Only her record has been altered.  I am confused as to why this should have happened since she had certainly not even met my father at that time - and did not marry him (and change her surname) until 1945.
There is a note and initials, which I cannot decipher, beside the amendment but this has been partially obscured by an old, adhesive tape repair to the page.
Any ideas, please?

[Girl Guide]

Welcome to Rootschat Edmin 

The 1939 Register records any marriages that occurred after that date.  These additions/alterations were done by the NHS for many years after 1939.

What you are seeing is the addition of your mother's married name.   I see that the marriage was in 1945 in the Chatham registration district.

Any change of name was usually noted even in the case of males where that was brought to the attention of the NHS.

[Gadget]

A very good description of the 1939 Register, including the involvement of the NHS, is given here:

https://www.familyhistory.co.uk/1939-register/

[Girl Guide]

Looking at the original it looks as though there is a date of 19.11.45 and the letters DHQ a space and then what looks like an N.

The letters may well be an area code.  If you look at the top of the page on the left, you will see an E.D. letter code of DHRK.

[JenB]

DHQ was the area code for Gillingham municipal borough
https://www.findmypast.co.uk/articles/1939-register-enumeration-districts

[ThrelfallYorky]

I think that many of us have found that sort of alteration, recording one's mother from maiden name to married, with the date in the 1939 Register - remember: though useful, it wasn't the same as censuses. It's rather nice to see, I think, and the exact birthdates given have proved helpful.
TY