As far as biggest bang for your buck goes I think 3 trident subs beats anything the crabs can muster several times over.
As far as Senior Service goes? Wouldnt that be the 'lady's' that hang around the back of Stonehouse barracks or the docks in Pompei? They have been providing a service for many years...so I am told.
Do they still have that damn foll rule where you cannot transfer from the 'senior service' to the junior? It is possible that I would be an ALM now if that had not been in place.