Inquisitor 78

[puzzled272]

Completely stumped on this. I've answers (hopefully correct) to all unstarred clues and have 10 of the 11 letters for the speakers name. Also have 2 of the five starred clues but have too few ideas of how they might be used.

First question: The answer to 23ac

Where to find closely packed thematic items of former "King"? (5)

is INCAS (from the down clues); and of course
INCA'S could be 'of former "King"' but I don't understand the rest of the clue (hence only 10 out of 11 letters). IN CASE (-E) kinda works but that would not fit with the form of the extra packed letter in other clues. Do you need to know the theme, or quote, or source, to answer
this one completely? or is it a clue to the source? i.e IN CAS+something

As for the speaker presumably, it could be a the author, a character, whatever?

Any input, without giving the whole game away, would be much appreciated. (Just hope it isn't as obscure as the Milligan quote of a few weeks ago! haven't rushed out a purchased the ODoHQ as a result of that one)

[novalis]

Incan = OF former kings
in + can

[Rapparee]

Novalis has given you the correct answer to 23a.

The preamble states that all but one of the unstarred across clues has an extra letter packed in. 23a is that one exception so you need to look to another across clue for your 11th letter.
Read cryptically, the answer to 23a provides a hint to one of the words in the quotation.
The speaker is a living person well-known in the world of sport.

[puzzled272]

Many thanks to you both.

[puzzled272]

Found my error, I'd misread the first word of 31ac.
Sloppy! My thanks again.

[puzzled272]

Done! OK, so now I'm kicking myself. Should never have missed that one as my clan are BIG fans.