Remember that horizon for single rotating array is likely higher (significantly) in the first place, and this is a modern AESA after all. Confirmation will be done immediately, there's no need to wait for second pass. Radar scans same +-60 sector during rotation.
I don't see escorts meeting chinese surface units or normal airpower, unless it's some case of Leyte, when their job is honestly to die for someone's else mistakes.
Normal Chinese long range threat is YJ-83 or YJ-18 from 21" TTs, of which they have 6. Of 6, 2 will be realistically be loaded with heavy decoys 100% of time, and likely at least one with torpedo just in case.
And vise versa, knowing that Constellation is main escort, it won't probably take too much brainpower to try to arrange missile pattern from 60/180/300 deg relative to convoy direction of advance... I.e. things are relative, and (especially when there's no money for 4 arrays) Europeans didn't choose high rotating arrays out of sloopiness.
CAMM-ER isn't UK weapon(only CAMM), and SeaRam blk.2 is ~20 km class.

Both are same thing - ~sub-100kg weapon(SRAAM adoptation) with all the possible trajectory optimizations. 10km is Chinese HHQ-10, which is substantially smaller(even if it looks similar).
SeaRAM succesfully outcompeted CAMM in Canada, after all.
People often don't really appreciate how big US "small" weapons actually are. ESSM mk.2 is not that far from some of the better systems which major navies use for their area defense (Barak-8 for example)