I'm glad you liked it! right on both accounts, I took out the "shuffle" and added back the "an" to the 2d clue that I accidentally dropped somewhere in rewriting the clue. Thanks for catching those!
Thanks for a very entertaining, if somewhat enfuriating, cryptic. I had to "cheat" on some of the clues.
20A Nasty! Seeing Y as the result of "young" I couldn't understand where the initial C came from; of course, I should have remembered the obscure baseball player, that sport being so very popular in the UK!
5A "Pill bug" is not a common name in the UK.
13A "Reagan" - definition by example?
6D had me mystified! I assume "ability" is SKILL but then I'm lost.
9D I assume "Pair of" means the first two letters of "jingoist" but I have never seen this indicator before.
23A In the UK, I've never heard of the Caldecott medal! CALDE must be a very obscure way of saying "hot" in Spanish.
24D Here we go again! US spelling foxes UK solver!
29A This one had me tearing my hair out (and there's not much left to tear at)! More US spelling and "Lorne Michaels" - who he?
27D I thought I'd solved the blighter then that US Z appeared! In the UK you are more likely to see S.
For 6D, it's a spoonerism of "cool skill," leading to Schuylkill (a very American river, apologies). For 9D, I've seen "pair of" to indicate the first two letters of something fairly commonly, tho maybe it's just a difference in which cryptics we're doing. "calde" is apparently not as commonly translated as 'hot' in Spanish as I initially believed, sorry about that! Lorne Michaels is a very famous TV producer over here, he founded and still runs Saturday Night Live and has been a background presence in American pop-culture for almost 50 years at this point