Hello Neil,  I believe I qualify as having “WS32 extensive experience including off shore”.    I have never had a need to remove my cockpit floor while at sea.  Saraband’s floor is bolted down with 12 1/4” bolts.   With that said, my cockpit floor is in 2 pieces.  A locker with my propane bottles take up the aft 1/4.  The fwd 3/4 can be removed independently.     Though only slightly related, I must also mention that my cockpit drains are turned 90 degrees to a horizontal angle and re/run out the stern.  The seacocks have been removed and the holes fiberglassed over.  Doing this will give you MUCH easier access to your engine room.   Good luck with your project.    Dave