If we are talking plaintext, the article is generally used. Omitting it is a kind of shorthand that we have become used to and is used in court papers and the like almost as an abbreviation.

Don't sweat it.

This is a tough question, mainly because you are dealing with legalese (... the party of the first part, in compliance with the said regulations put forth by the party of the second part...)

My wife has a slavic language as her mother tongue. She is ALWAYS having problems about when to put THE in the sentence and when to leave it OUT.

My only response to her, and you, is "It doesn't SOUND right that other way."

You might check the link.

...or when referring to a person or entity.

Do not use "the" before "said" in the middle of a sentence when referring to an object (such as an apartment).

Just an instinctive rule of thumb for me as a native speaker. I am not able to substantiate in the least grammatically. :)

just read that it is also the difference btw American and British English
it s a legalese

I quote:
The use of said as an adjective meaning aforementioned comes from legal and business writing, and
While the OED Online may give a determiner in all its examples; said is not always used with a determiner. I don't see how "of said child" can be grammatical if you don't consider said a determiner. In fact, I think these Google Ngrams make it clear that said is a determiner in American English but not in British English