My wife and I just completed the "Norwegian Lights" cruise which we thoroughly enjoyed. It was a bucket list cruise getting into the Arctic Circle and seeing the northern lights whilst in port of Alta.
This is our 6th P&O UK cruise and some things have changed that made it a lesser experience. Firstly P&O UK now charge for room service (except the limited breakfast menu). When I queried this I was told that they are just bringing room service in line with hotels to which I replied "but you normally don't prepay for meals at a hotel". Secondly P&O UK have now taken internet charging to a new level so much so that we just didn't bother with it for the first time ever. Thirdly freedom dining is anything but if you want a table for 2 then expect a wait time of 30-45 minutes!
Our balcony cabin was on the Lido deck which was great for access to the Horizon buffet and Crow's Nest. The ship is looking a bit tired but I'm told it is going to a refit in Jan 2019. I have thrown out TV's better than the one that was in the cabin.