Tourist,
You obviously know AW well then - nothing comes cheap. What is more expensive? Fitting a strengthened floor and extra rear undercarriage wheels to a Mk1. Ramp aswell maybe - but the SK 4 never had one and the one on the Mk3 is debateable as to its utility v cost. I can't think of much else - but you probably can.
Or do you cut up the tail section of a Mk3, plus fitting a Blade Fold Head and motor? I'm not going to comment on whether the Mk3 construction is marinised or not cos I don't know. In fact, I don't know the answer to any of this... any engineer types out there? What would be cheaper?
MM4 - We still need a dedicated (perhaps scaled back CHF). With a suitable ac......