Hi Col & Sue, I have not been on this amazing cruise yet!
To my knowledge you don't have to remove the luggage from the cabin, if you have the same one assigned for the next cruise. A Purser will escort you off the ship to go through customs and immigration again. They will then escort you back on the ship to do your check-in at the Info Desk onboard. If you do have a Cabin change between the cruises they will move the luggage to the new Cabin. You will also be given a new Sail & Sign card for the new cruise.
That's all I know about it as a non-professional. Congrats on this wonderful cruise.