You can buy wine package on board ( leaflet in cabin ) BUT all bags go through scanner each time you board, and you are asked if you have any bottles, sometimes you could be lucky other times not.
Have now been on both Ocean Village ships over the last 2 years. Yes drinks packages are available but wine tends to be around £10 a bottle upwards. You can purchase spirits duty free in the shop but if you wish to consume them in your cabin you pay £6 extra per bottle for this privl!idge. My advise would be if you like a gin and tonic or a brandy/whiskey nightcap etc. Buy some from the supermarket in the UK and pack it in your suitcase. I have done this twice now and there has been no problem. It was a tip I picked up from another cruise comments site. If you try to carry drink on board they will take it off you and store it till the last night of the cruise. Hope this helps.