carriers have been very useful in the past
Yup. That is a bygone era for a country which lost its empire in the 1940s. Carriers are primarily a weapon of war for an imperial power. Britain has no empire, consequently has no need for such an imperial weapon. Britain
is an aircraft carrier. Sardonically referred to as Airstrip One as long ago as 1948.
RFA Mounts Bay that was positioned out in the Caribbean for the hurricane season.
As I pointed out, an RFA can do a little bit of useful work in such an area, but only if it doesn't have to support an F-35 airbase at the same time.
In any logistics operation, the big tonnages go by sea
Yes, and they go by cargo ship or by airbridge, not by warship.
The really desperately needed stuff that is most urgently needed goes best by heavy lift cargo aircraft. They operate best from airfields outside the immediate vicinity of the airlift destination.
A warship optimised for F-35s isn't as well suited as a proper airfield and can never hope to handle meaningful quantities of air-hauled cargo as the massively more appropriate fleets of C-17s and A-400Ms and C-130s can from appropriate intermediate points.