The Citizens800 web-page to start from is www.citizens800.org
… and the page introducing their resources for schools is HERE …
Don’t be put off by all the AQA coverage on that first schools page if you teach other specifications as the resources being developed will be useful to everyone, including at KS3 and A level.
At the moment, they include animations and video material on the project’s YouTube channel on King John and Magna Carta, the battle of Sandwich of 1217, Great Revolt of 1381 with plenty more material to come on later periods of history.
Even if you don’t teach or have never heard of the battle of Sandwich the animation is worth a look for the demise of King John and the departure of Prince Louis!