Primed to Begin by Spud

Puzzle explanation

This puzzle marked the introduction of equal marriage in England and Wales, for couples of the same or opposite sex. Extra wordplay letters spelt “Observe prime numbered clues’ first words”. In numerical order, these gave “Highlight one of four couples, unchosen names, fully or mostly highlighted, coming as guests”. The highlighted invitation involved choices of either ADA or ADAM and either EVE or STEVE, with the two unused names to be written below the grid as guests.

Highlighting an A in the top row to make the first section “A WEDDING” was accepted as long as the highlighted names were not ADAM AND STEVE (making a total of 34 cells). Alternatives for the guests’ names were not accepted. Many alternative names submitted were not highlighted at all (REG, ROY etc) or not mostly highlighted (LEW, JOY etc). The ones that were sufficiently highlighted (ED, DI, INGA, LEA, JO, ADE) were not involved in the highlighting choice, and were therefore not the unchosen names referred to.

Clue explanations

Conventions: * = anagram, < = reversal

Across
1 ACRE A + C[O]RE
6 RARA AVIS RA + [B]RA + A + VIS
12 FLEWED (DEW + [S]ELF) <
13 INGANS (Unchose)N in GAINS *
14 FACT FAC[E]T
16 ROY RO[R]Y
19 JOINT (FULLY + JOINT) * = (FUN + JOLLITY)
20 ANAGRAM (A + G[E]RMAN(e) + A) *
21 SEA S[P]EA(k)
22 PTISAN (IN PA[R]TS) *
24 SCYTHES SCYES around TH[I](n)
30 DIPNOAN DIP + NON[E] around A
34 DECREE DE[N] + CREE
36 ERE E + R[U]E
37 VETOING (C)O(me) after VET + IN + G
38 MANEH MANE + H[M]
39 DEPTH DE[B]T around P + H
41 E’ER (p)EER
42 ELUL ELL[E] around U
43 CHAIRS (Guest)S after AIR after CH
44 PNEUMA (NE + [R]UM) in PA
45 HALF STEP H + ALF + ST[E]EP
46 KSAR [D]ARK’S *
Down
1 AFFRAPS RAP in [C]AFFS
2 CLAP (High)L(ight) in CAP
3 RECLAIM I in RÉCLAM(e)
4 EWT [L]ET around W
5 GEMARA GEM + ARA(b)
7 AD REM (DRIVE − IV) in AM
8 ANY JOY YOJANA < with Y[U] for A
9 AGNOSTIC (IT’S NO CAG[E]) *
10 VANISH VAN[S] + ISH
11 IN-KNEED IN(to) KN(ock) EE(jits) + D
13 IODIC (DI(n) + C) after IO
15 ASANA AS + [F]AN + A
17 UTAS (UTTERS + EAS) − TERSE
23 SANSERIF (OR ONE OASIS OF) * − O − O − O − O
25 PIRANHA (A + HA[I]RPIN) *