If you sit at the back of the balcony on 10 i.e under the one above you are not overlooked. However you have the option to move out to the outer balcony.
However it must be said the ordinary balcony on the Grand class ships, including Ventura are of a much larger size than those on Britannia so are better.
Deck 11 is between two cabin decks so should not have noise from communal rooms.