You need to go into advanced > events, and edit the Watching Media event for your entertainment area.
This is generated if it does not exist, by UpdateEntArea, which is the source for all the automatic logic. Look in src/UpdateEntArea, and the appropriate subsection if you want to see the logic used.
I think it must be the events that I need to get at. I'll check the logs that phenigma pointed me to when I get home and check it to be sure. Its not the actual scenarios that I want to edit, but the events that are triggered when the scenario is started or stopped. So for example I know that the "showtime" scenario for the lights is triggered when I press "TV". I can edit the "showtime" scenario no problem, but where in the "TV" scenario is the link telling showtime to execute? Also when I stop the TV scenario, another event is fired which is like the reverse of showtime, and puts the lights on again. This I can't find. I'll go through the logs tonight and hopefully that will shed some light on whats happening.
I'm sure its just down to me not looking in the right place. I'll take a good look again at the Events too, I went all through this setting up my Z-wave devices, so I got the hang of that part of it previously.
Thanks for the pointers guys.