MB....your question has a problem built-in to it.
If buying a current MK of the MGB....and not a new design and fully tested and proven Gearbox....it would only be worth what is can bring as scrap iron.
The 225 is history as far as the North Sea is concerned and by default....in all Offshore Operations.
Some military forces might continue to use it....but if they start seeing failures as has happened in the civilian side of things....then the 225 will find itself as gunnery range targets.