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An enjoyable challenge
Across
1 MAHLER (Gustav – composer) MAILER (Norman) H[ead] for I (Italian)
4 ADVANCED dd
10 JUMP LEADS (help to start car) JUMP (clear) LEADS (clues)
11 TWIST dd (Oliver Twist)
12 SASH (band) S[uch] A SH (quiet)
13 FIRST-CLASS (marvellous) dd
15 ICEBERG (calf – ice broken off glacier) I CE (church) BERG (hill)
16 DEALER (gives hands of cards)
19 ODESSA (port) (DOES)* AS< (when back)
21 PIT BULL (dog) PIT (mine) BULL (nonsense)
23 INQUISITOR (Torquemada eg) IS in I N (northern) QUITO (capital of Equador) [minste]R
25 SPAM (junk mail) MAPS<
27 STILL dd
28 TRUNCHEON (club) (CHUNTER ON)*
29 ARTISTRY (great skill) (STAIR)* TRY (with effort)
30 GROTTO (small cave) GROT (rubbish) TO
Down
1 MAJESTIC (royal) M[ention] A JEST (joke) I C (one about)
2 HOMESTEAD (dwelling) (SOME HATED)*
3 EELS &Lit hidden in [cr]EEL S[lithering]
5 DISUSED (neglected) D (daughter) S (son) in I SUED (took legal action)
6 ARTY-CRAFTY (into art) (TRAY)* CRAFTY (anagram indicator?)
7 CHINA (tea cups) IN in CHA (tea)
8 DETEST (loathe) D[elicat]E TEST (examination)
9 DARING (bold) L (length(s)) from DARLING (favourite)
14 VERSAILLES (French residence) AI (1st class) LL (lines) in VERSES
17 EQUIPMENT (tackle) MEN (chaps) in (PIQUET)*
18 FLAMINGO (bird) FLAMING (vivid) O (duck)
20 AVIATOR (pilot) hidden in [Ottaw]A VIA TOR[onto]
21 PROP UP (support) PRO (for) P[rofessor] UP (at university)
22 FIESTA (carnival) IF< (provided up) (TEAS)*
24 QUILT (bedding item) L[aundry] in QUIT (left)
26 SCAR (mark) S (small) CAR (saloon eg)
( )* = anagram [ ] = omit dd = double definition < = reverse
Thanks Falcon for an enjoyable puzzle and Jed for the blog, especially the parsing of 1ac, which eluded me, although I guessed the answer correctly. Favourite clue 5dn for its excellent surface.
6dn: I took this as “designing” = CRAFTY following TRAY*, with “fashioned” as the anagram indicator, the definition just being “Into making decorative objects”.
7dn: I would mark this as “& lit”.
A nice straightforward puzzle. Thanks to Falcon and Jed too.