Due to the landing gear the Merlin Mk3 cannot be lashed down in a manner suitable for ships, even if lashing points were added/reinstated. AWL suggest that the gear could be modified but I left the programme before the details / cost were provided. At the moment the Mk3 can 'visit' ships but not routinely operate from them.
Having seen what the 'coupon testing' material looked like when exposed to the simulated salt water environment I am not sure leaving them to rot is practical in any way. There has to be some protection added or the revised fleet life would not be long enough to convert all the CHF crews to type!
Please don't forget how tall the aircraft is before you try and park it downstairs!