I remember the ghoti one too, it's one of George Bernard Shaw's little tricks.
You were all right with the had hads.
I usually do it thus:
"John, where James had had (as in "had written" or "had used") "had had" (past perfect tense) had had "had" (past simple) "had had" had had (as in "had received= been given") a better result from the teacher.
I am also semi-colon/colon illiterate, I tend to use a colon if a full stop would also be possible. Is that right?
The that one is easier. "He said that (relative pronoun) that (demonstrative adjective) "that" (irrelevant whether RP or DA) that (RP) that (DA) said was correct.
I use these sentences in conjunction with the different pronunciations of "had" as a main verb or auxiliary verb and likewise "that" as an RP or DA.
My comma example is to ask students how many sisters I have in each of these sentences.
My sister, who is a nurse, works at the hospital. (I have only one sister- the commas surround extra information which is not vital to the understanding of which sister, because there is only one)
My sister who is a nurse works at the hospital. (I have more than one, but one of them is a nurse, without the nurse information we wouldn't understand which sister I was talking about)
Those 2 examples had a nasty doctor student make me cry once. My innocent little example had him screeching at me that I was a racist/facist and thought British people were superior to southern Europeans like him. Just because he didn't understand my commas. Diddums.
Now, if someone can give me a complete and brief set of rules for prepositions...I have 2 uni students at 4 o'clock who have an exam of 2 hours on Monday, solely on the use of prepositions, and beyond telling them "it comes with time/use/experience of using the language" I don't know where to start.