Note that D-Link have decided to brick a lot of their old smart plugs by disabling support in their app, so mine will have to go in the bin. Worth bearing in mind when buying any of these things.

In theory you can automatically create a calendar event from an IFTTT recipe, so you could automatically create the switch off event. But I've never done that so you'd have to experiment. At this point it starts to get a bit crazy though. I wish IFTTT would just allow more complex recipes...