Sven,
Far too logical and ignores one vital point. The Puma is beloved of several senior RAF hands who don't want to be seen accepting a RN cast-off. The SAR-H cancellation may well force a radical change in mindset. Who knows, there could be a nice consultancy job for you if that occurs....
SK3/3A/4/6 to a new Mk8 standard akin to the S61 Triton with all of the best Carson Bits and integrated into SKIOS. Capable cabs, UK offset and already amphibeous. Scrap Puma 2 to realise the WLC savings of driving a type out of service. If you're really daring, scrap/sell Merlin as well and modify 100+ of them.....
