True, but then they did totally rebuild them with new engines and rotors, the Wessex simply plodded on as delivered.
No it didn't. Wastelands replaced the piston engine with a single turbine, it was then installed with two turbines connected to the main gearbox via a combining gearbox at the original angle.with the engines positioned as ideal vacuum cleaners.
The Puma's 'rebuild' consisted of replacing the engines via the quick release system, the gearbox and head the same way and rebuilding the inside of the cockpit to accept the Super Puma's control systems.
The blades came with the head.
Why they didn't they install the 900 ft/min impact single wheel undercarriage of the Super Puma is something I cannot fathom.