Not too difficult, I thought - it took me 20 minutes, including the time needed to check the answers to 40ac and 20dn (see comments below). One of these days I really am going to sit down and learn all possible cricketing terms off by heart...

As ever, * indicates an anagram.

Across
1	CHIRPIEST - CHIT, around Raspberry + PIES
6	RECOGNISED - (designer)* around COmpany
12	NOVELLO - NOVEL + LO
13	GLUTAMATE - GLUT + AM + ATE
14	SKIED - SKIrtED
16	OF THE ESSENCE - "Key" is the definition; the cryptic indication is to OF THE ESSEN CE, where CE = Church of England. I'm not sure that "the" is indicated by the wordplay
17	PLANTATION - PLAN + TATI (the late film director Jacques Tati) + ON
19	FALL ON DEAF EARS - FEARS, around ALL + (of Aden)*
22	PROLOGUE - PRO, + LOGUE (sounds like log, = record)
24	NADINE - A DINE after N
25	REINSTATES - REIN + STATES
26	TESLA - set, reversed, + LA
29	DACE - ACE after ponD
30	FRUITFUL - double definition
32	PICTORIAL - PLace around Victoria
34	TAIL-ENDER - AIL in TENDER
35	NORMANDY - N + OR (other ranks) + MANY (= legion) around (key of) D
36	SPAM - double definition - SPAM in the sense of junk e-mail
39	SPELL - P in SELL
40	EXTRA COVER - EXTRACt + OVER. As usual, it was the cricketing clue that threw me; I'd never heard of EXTRA COVER in this sense and had to resort to artificial aids to work out what the second word was
42	DOMAIN - D, + I in OMAN
44	TONING UP - IN, + PUG (= boxer) reversed, by TON
46	LICENTIOUSNESS - (lust is one sin)* around CE
48	BOTTOM LINE - BOTTOM is a character is Shakespeare's Midsummer Night's Dream (abbreviated to MND here)
49	PARKING METER - this would be the Rev. Spooner's version of "marking peter", where peter is a slang term for a safe
53	SEISM - IS, in SE (South-East) + ChathaM
54	INTUITION - I + N + TUITION
55	STATUTE - T in STATUE
56	BRIDEGROOM - BEG ROOM around RID
57	ENACTMENT - CourT in (ten mean)*

Down
1	CIVET - hidden in quiTE VICious (reversed)
2	I'LL BE BOUND - ILL, + BOsUN in BED
3	POOLSIDE - sloop (reversed), + IDE (sounds like eyed)
4	EAGLE - E, + Elgar reversed. "Score" here refers to golf
5	TRUNCHEON - (turn)* + Confident + HE + ON
6	RYAN - (NAY + R), reversed. Reference is to the film "Saving Private Ryan"
7	CRADLE - (declare)*
8	GREEN CROSS CODE - GREEN, + COD (to kid) in CROSS + E
9	INSTALLATION - I, + STALL in NATION
10	EXITING - EX + I +ThING
11	UNCONFINED - UN + CON + FINED
15	DANCE HALL - (Lad he can)* + L
18	PRATTLER - P + RATTLER (= rattlesnake)
20	LIDOCAINE - LINE around DOC + AI. LIDOCAINE was new to me, but the wordplay was helpful and the -CAINE ending was fairly predictable for an anaesthetic
21	AMELIORATE - first letters of "Avoid motorway excesses", + oil (reversed) + RATE
23	STEP-PARENT - (test paper)* around examiNation
27	SAILPLANE - SnAIL, + PLANE (sounds like plain)
28	BRIDGE-BUILDING - double definition
31	FANTASIA - FAN + TASmanIA. I thought this was a very clever clue with a beautifully misleading surface reading
33	WELL-INFORMED - LL IN FORM, in WEED
34	TEST TUBES - butts (reversed) in TEES
37	MINISERIES - MISERIES around NI (Northern Ireland)
38	CONSUMMATE - CON + SUM + MATE
41	OPERATIVE - PE + R, in (a vote I)*
43	POINTS AT - P, + (station)*
45	NUTTIER - NUT (National Union of Teachers), + TIER
47	ONE-TWO - O (a circle, hence "ball"), + NET, + WO (without)
50	KINDA - KIN, + DA (District Attorney)
51	TAUNT - hidden in greaT AUNTs
52	FIRM - F, + odd-numbered letters of "in Rome"