Solution to Coronation by Chalicea

 Coronation by Chalicea - Solution

Extra letters gave 'Shade forty-five cells: four places and an iconic item once in each'. Solvers were required to highlight THE STONE OF DESTINY (that sits under the King's throne at the coronation) and SCONE, WESTMINSTER, ARBROATH and EDINBURGH.

Across: 1 Scones, 5 Rickshaw, 12 Hernia, 13 Axe, 14 Neon, 15 Articles, 17 Nannoplankton, 18 Fewest, 20 Minster, 21 Restroom, 26 Out-half, 28 Epochal, 29 Paratha, 30 Decarbs, 33 Theatral, 36 Loudens, 39 Onsets, 42 Prestigiators, 45 Selenian, 46 Fiat, 47 Din, 48 Burghs, 49 Day-sight, 50 Eatery. 

Down: 1 Sinner, 2 Ohone, 3 Ergo, 4 Snips, 5 Rialto, 6 Catnip, 7 Sects, 8 Helots, 9 Akene, 10 Wastrels, 11 Tea, 16 Rammed, 18 Feuar, 19 Erato, 22 Thar, 23 Cocas, 24 Scat, 25 Cabas, 26 Opalised, 27 Fatsia, 31 Burley, 32 Anting, 34 Hognut, 35 Lastly, 37 Opera, 38 Deeds, 40 Nitre, 41 Toise, 43 Alga, 44 Ran. 

Across: 1 S: S(i)C(k) [S]ON E(at)S, 5 H: RIC[H] + HAWKS*, 12 A: HE[A]R AN, round I, 13 D: A X E[D], 14 E: NE + ON[E], 15 F: AR I CLE[F]S, 17 O: {PLONK AT INN A NON[O] less I}*, 18 R: FE W [R]EST, 20 T: MIN[T] + STER, 21 Y: {M[Y] SO RETRO}*, 26 F: {HAUL OF[F]}*, 28 I: EP[I]C around O + HAL, 29 V: PA (t)R(e)A(t)T(o) HA[V](e), 30 E: DE[E] CAR BS, 33 C: THE [C]AT R(e)A(l)L(y), 36 E: (c)LOU(t) DENS[E], 39 L: {[L]ETS SON}*, 42 L: {GRIS[L]IEST PART round O}*, 45 S: LES[S] EN I A (unk)N(own), 46 F: FAT around I[F], 47 O: D[O]-IN, 48 U: (b)[U]G(s) in SHRUB<, 49 R: YA[R]D + SIGHT, 50 P: (s)EATE(d) + [P]RY. 

Down: 1 L: CRIMINA[L]NESS* less {I SCAM}*, 2 A: ONE around HO[A], 3 C: [C]ORE< around G, 4 E: SNIP[E]S Double definition, 5 S: O[S]T L AIR<, 6 A: CAT + P[A]IN<, 7 N: SCE[N]TS with E moving up, 8 D: HEL[D] OT S(acred), 9 A: AK[A] + first letters, 10 N: STER[N]LAWS*, 11 I: [I]T EA, 16 C: [C]RAMMED, 18 O: FEAR around [O]U, 19 N: ETO[N] around R(e)A(d), 22 I: T(angled) HA[I]R, 23 C: SAC[C]O C<, 24 I: {ACT [I]S}*, 25 T: CA BA[T]S, 26 E: O PAL[E] (d)IS(c) E(namel) (adde)D, 27 M: FAT SIA[M], 31 O: (t)R[O]UBLE(s)* + Y, 32 N: AN[N]OTATING less TAO*, 34 C: HO[C] GNU (a)T(e), 35 E: L[E]AST L(ad)Y, 37 I: Hidden (c)OP[I]ER A(dvertised), 38 N: DS around [N]EED, 40 E: NI TRE[E], 41 A: TO I(nland) SE[A], 43 C: (s)[C]AL(e) + AG<, 44 H: (p)R(e)A(c)[H](i)N(g).