UK, as things stand, isn't exactly big operator neither for aster series
Type 45: 48 A50 * 6 = 288 Aster 30 cells.
Now of course we won't be a big Aster 15 operator as we've had all of ours rebuilt as Aster 30, because we've standardized on CAMM for short range air defence. So looking at CAMM cells as an Aster 15 equivalent:
Type 45: 3+3x 24 CAMM
Type 23: 4x 32 CAMM (to be retired)
Type 26: 0+8x 48 CAMM
Type 31: 0+5x ? CAMM
= 200 (+ 200 + ?) CAMM cells
France:
CdeG: 1x 48 A43
Forbin: 2x 48 A50
Aquitaine: 4x 16 A43
Bretagne: 2x 16 A50
Alsace: 2x 32 A50
Amiral Ronarc'h: 1+4x 16 A50
= 112 x A43 cells for Aster 15
192 (+64) x A50 cells for Aster 15 or 30
Italy:
Cavour: 1x 32 A43
Trieste: 1x FFBNW 16 A50
DDX: 0+2x 48 A50
Orrizonte: 2x 48 A50
Bergamini: 10x 16 A50
Thaon di Revel:
Full: 1+2x 16 A50
Light+: 1+1x 16 A50
Light: 2x FFBNW 16 A50 (to refit to full)
= 32x A43 for Aster 15
288 (+128 + FFBNW 16) A50 for Aster 15 or 30
So the UK (488) clearly outstrips France (368) and narrowly outstrips Italy (474) for deployed + planned AAW cells, and likely outstrips both for deployed + planned Aster 30 given the UK uses only Aster 30 in A50, while France and Italy mix Aster 15 and 30.
Hardly an issue when we chose to deploy Tomahawk from subs, not from surface combatants. And no Tomahawk compatible VLS cells until Type 26 enters service rather limits the number we could have at sea.