That is the point - we don't need hulls that can do EVERYTHING - we need a few that can frighten a few Somalis, sit and chase the Spanish Coastguard in Gibralter Bay and watch over the Falklands Economic Zone etc etc
Using 45's for that sort of thing is a dreadful waste of money
Last time I looked, we don't use 45s for any of that, directly. Falklands EEZ - HMS Clyde with support from HMS Protector. A 23 or a 45 does APT(S) from time to time - not least to exercise long-range independent deployments. Gib - two small (16m) patrol craft which is actually all we need unless we want to start shooting. Do we actually want to start shooting with our NATO & EU partner?
Any ships on ATALANTA are also meant to be able to go upthreat in the Gulf if required, which some sort of lightly armed corvette most certainly could not.
That's the problem with this
PR job. It's nothing to do with better assets for "low-level tasks" and everything to do with CGS trying to chisel money from the T26 budget to fund land systems, rather than a de facto increase in hulls. More hulls = more manpower which the RN most certainly won't get and guess what - it's the lower-level tasks that actually require the majority of manpower. The FP watch bill can be significant, which means larger crews - (I'd be surprised if a "corvette" to do these sorts of tasks would require less than 75 bods, plus extras like LEDETS, boarding parties etc). That is going to lead to a larger and more expensive ship than people are envisaging.
All of that means that you'd actually end up with broadly the same number of hulls (one, possibly two extra if you're lucky), but fewer of which will be deployable in a real threat environment. And to address S41's point re task groups and "other" RN tasks - it's fair to say that (as with the Army and the RAF) if a full RN TG is required, other tasks will be gapped for the duration.
What that means is that you actually reduce your overall capability to fight wars, which is not the stated intent.
Anyway - I'm sure this belongs elsewhere than the carrier thread.......