I saw (1994) ZE449 on the jig at Westland’s (Weston-super-mare), and it had been rebuilt to as good as new. Westland’s wanted to 'zero hour' the airframe but the MOD insisted that used components (engines / transmission) were used, therefore a nominal 'airframe hours' was guessed at in the absence of technical history.
It looked in far better shape then the Puma fleets own cut and shunt that was also present. This had, from the floor up one that had been to the bottom of the English Channel. From the floor down (inc cabin floor) one that had been involved in a ground taxi/roll over/fire incident. The tail boom was from a third one, and all 3 registration serials were written on the airframe!
As has already been alluded to, often if not usually rebuild budgets are unrealistic when new purchase is the most cost effective way. Flight itself is only 100 years old yet we are flying 36 year old helicopters, whilst Third World countries are flying contempary helicopters having resigned their own Pumas to museums. The old girl has done her bit (and more) and should be replaced with new, off the shelf, medium sized helicopters.