The car park that RCI usually use is right at the end of the docks and you should try and get free parking but if not book there car park you drive in drop your luggage park up and away you go short walk and your on the ship.?
Not been on RCCI. from southampton. But CPS. who deal with Pand O and most other cruise lines are 100% . Our car is not that valuable but each time we have left it over the last few years has always been in the same condition we left it. I can only say that if you have a very valuable car think again and find an alternative way of joining your ship. CPS are faultless and even if we had a more valuable car than our own I would not be afraid to leave it in their care! My husband does not like me driving his pride and joy, but trusts CPS more than me!
Forget going by car, go by train, plane, taxi , coach if you are so worried.