On the teens Vs families thing. I think teens maybe do spend more money, it's just that they have less ability to actually get to a park, so unless it's somewhere like Thorpe, your catchment of the market if reduced.
Even taking picnics though, and having AP's, Family_Furie will still spend around £20 each visit to Alton Towers. It's not much (fiver per head), but we're seasoned veterans. You see most families spend quite a bit, as it's their "big day out" of the year.
Obviously somebody has cottoned on, as both Alton and Drayton Manor have had bumper years since turning more "family".
However, the parents still drive the visits, and especially at Alton, they demand to be entertained. If there's nothing new for them, they're not going to pay £36 year in and year out to take the kids on a rethemed Ugswinger. Sea Life is a great addition, it gives more 'value' to the day for a family, but 9 times out of 10, oneof the parents also demands rides for them to close the 'value' deal.