Hmmmm. Buy an aircraft designed for trooplift/assault and Combat SAR/SpecOps, with a folding mechanism that defies description, fit it with a UK-specific radar and comms / datalink fit and bring it into service in limited numbers as (probably) the only type operator in the world? Not obvious at all, I'm afraid SaN. Not at all sure that she'll be fast enough or with sufficient endurance to do the full MASC role either.
Or.......buy a proven, in-service aircraft, designed for the MASC task, compatible with our principal allies (and the French!), with all the speed and endurance you'll need and a funded development path to keep it in service for at least another 25 yrs.
Or.......muddle around, take a very good set of avionics with some very good capabilities and integrate them into a rotary wing platform that is either antediluvian or with a limited airframe capability in terms of speed and endurance at height.......oh b8gger!