I think, if you look at the details of the withdrawal of FRI's from the crabs, it applies to everyone except FJ Pilot/Navs and RW Pilots. Hence anyone who might be useful to the FAA is being actively kept in the junior service. I guess you could take a fun-bus, kipper fleet or tanker pilot, but then you'd have to put him through ACP/OCP, hence with the same associated risks and costing as much in training as a nozzer off the street - who the RN will get more years of service from?