Simon, next time you speak with whoever calls the shots in that scout partool, be crystal clear about what you consider an update and what is a redesign of the site. Tell him what you agreed with his predecessor, and if he wants more than that, he has to open his wallet (well, probably not his private wallet...). If he is still listening, give him an estimate of how much it would cost to have the changes made that he wants and approx. how long it will take.

Also, remind him that there is this little thing called working hours, and allthough you (perhaps) are willing to put in a couple of hours during weekends, that will, of course, be at weekend rates. Do your homework on the costs, and let him take it or leave it. Best thing is having it in written, as a contract. In it you can also include what he /someone in the scout patrool have to provide themselves, like images, text or whatever. Don't sell yourself too cheaply, that is not professional.

This thing about not getting a 'thanks', I know that from my own experience. Remember that for the next time they come running for another update. Good luck to you!