"it just needed some more work."
and most of the Defence Budget ......................
The trouble with an anti-sub MPA is that where we know we can fly it - NW Europe, N Atlantic it is very unlikely we'll have to "protect" the new carriers
Where we might use them in anger - say in the Middle East/N Africa/W Africa - there are hardly any subs to look out for
Further afield we come back to the aircraft basing problem for very long distance naval deployments