Hi Mate
Did our first ever cruise last year with p and o on Ventura went to Spain, Portugal and Guernsey and after all our apprehensions we loved it and can't wait to go again!
We didn't do drinks package either, drinks were cheaper on board than they are at hall and Woodhouse in portishead!
You are wise to not tick the upgrade, we choose a cabin similar to what you have and it was fantastic, the balcony is a great option
Loads for everyone, including kids to do, I'm sure you will love it.
You going from Southampton?