I think that you are right that those inside UK waters can be fitted for but not with TAS and CAMM. In my vision you would still probably want to have this on vessels patrolling the falklands, gibraltar and the Caribbean. I would see this as 16 fully configured, and 8 basic.I don't think it would be necessary to fit all of them with CAMM a modular approach such as the Stanflex, with ships outside of UK waters fitted. Also the production line would be much longer c16-20 (if they replace MCM, OPVs & Survey ships plus some frigates). I think the RN ships need longer range as they have to work over longer distances with less RFAs?
TAS, CAMM, Phalanx maybe only sets for 8-10 ships?
As I see these patrolling alongside a JSS for significant deployments, I think range to some extent can be sacrificed.
Also, I see these ships being operated in the same way as HMS Clyde with a high percentage of availability. Building one per year continuously means a 24 year lifespan.