Enigmatic Variations No. 857 – Exactly by Lato

The preamble indicated that ten clues had an extra word each of which defined ten otherwise unclued entries. A further unclued entry (of three words) was said to explain ‘exactly’ where these entries could go.

The unclued grid entry was ‘TO A T’ (bottom right-hand corner) and all of the entries defined by the ten extra words could be preceded by ‘T-‘ to give an entry in Chambers. 

*(XXX) – anagram
[x] – letter(s) removed/unused
{xxx / XXX} – extra word / grid entry

Across
4 PACKAGE  [b]ACK in PAGE (attendant) – {carry / CART}
7 RUINATE  RU IN ATE = ‘a true’
8 BUREAU  UR (uncertain expression) in BEAU (lover)
9 ERGATE  E (Spain) *(GREAT) – {union / JUNCTION}
10 LANOLIN  L (lecturer) A (one) NIL (nothing) ON reversed – {dress / BANDAGE}
12 STULL  S[tupidly] T[urned] U[p] L[ate] L[ucky]
13 PRY  PR[a]Y (I ask you) – {garment / SHIRT}
14 OSIERS  hidden in ‘hoOSIER State’
16,22 PASTORAL  PAST (previous) ORAL (exam)
18 CATCHER  CAT (chap) CHER (actress) – {bird / RAIL}
20 OCULI  CU (copper) in *(OIL) – {dungeon / CELL}
23 RAS  R (rule) AS (like)
25 ALOO  AL (little boy) OO (loves)
26 MOPER  MO (little Maureen) PER (a)
28 GODDAMN  GO (ready) DD (designated driver) *(MAN)
30 MASS  dd
32 TENNER  homophone or ‘tenor’ (drift)
39 REGALES  REGAL (royal) [b]E[s]S
40 TOBIAS  OT (books) reversed BIAS (unfairly influence)
41 CRAVAT  *(CAR) VAT (tank)
42 LEPROSY  PROS (tarts) in LEY (line) – {save / BAR}

Down
1 CREEP  C (caught) PEER (fellow) reversed
2 AURORA  AU (gold) OR (gold) in RA (Argentina)
3 RIGA  RIG (set up) A (academy)
4 PATE  P (prince) ATE (upset)
5 ATELIER  E (English) in *(TRAILE[r]) – {set / GROUP}
6 AUNT  U (posh) in ANT (soldier)
8 BASRA  S (southern) in ARAB (homeless boy) reversed
11 SOCLE  *(CLOSE)
15 SONDE  SON (issue) D (Dutch) E (electronic)
17 AULA  [p]AULA (girl) – {angry / CROSS}
19 TAPS  SPAT (petty quarrel) reversed
21 CADRE  D (Germany) in CARE (be anxious)
24 SONATAS  O (nothing) in SATANS (devil’s) reversed
27 BESET  E (east) in BEST (first)
29 MALAGA  LAG (delay) in MAA (bleat) – {traffic / COMMERCE}
31 SOAVE  O (old) in SAVE (be economical)
33 RESET  E (ecstasy) in REST (support)
34 CERO  hidden in ‘aCE ROdman’
35 SLAP  PALS (friends) reversed
36 ASBO  S (is) in A BO (a man)
37 TONY  N (new) in TOY (play)
38 CIAO  homophone of ‘chow’