Here are some HEAVY pointers for your 'thick' family (your words!!)
22. Abbreviation for Fellow i.e. a shortened bit not another word so what LETTER can stand for fellow and that is the first letter of the river (no longer in existence)
32. You haven't picked up on the man of letters. Not a writer, who handles letters on a daily basis. Use that word to google and find a place in London and read about it. I'd not heard of it beforel
47. As we don't know the compiler's name, well we do actually, Neville, but that is hardly going to fit in a clue. So how else, in a normal sort of way, would he talk of himself. So you have the beginning and you've very cleverly got the ending from other clues so it shouldn't be difficult to fnd the line now.
57. You've focussed on the wrong word in the two you quote. Have you heard of the Savoy Hotel in London, that's the vegetable, a type of cabbage but is not the answer. A different word for norm - do you google at all. Put norm-synonyms to find alternatives.
87. It's a table where numbers are given letters and the letters represent ELEMENTS (Hence the clue elementary). Use the numbers in the clue to spell out the word. Also google RA - so two ways to get this answer.
I'll probably get shot down for giving you so much help but if you can't answer the questions now, then you must really consider whether cryptic quizzes are your thing.