This post encouraged me to look further afield than P&O and in particular SAGA.
I know the post revolves around suites but I am going on Britannia with my wife for two weeks in May this year in a standard balcony, at the select price, in a position chosen by me. I compared this cruise with an equivalent SAGA cruise at roughly the same time and route in their standard balcony, also in a similar position chosen by me.
I readily accept that there are a lot of extras thrown in with SAGA, and the cruise would have had three extra ports, BUT the difference was, roughly, an eye watering £7000, which makes it about three times the cost of P&O!!!
I'll stick with P&O for the time being.