My pleasure. Looks like there are others, but not all are specific to that one event. I noticed a news story from 1964, in b&w.
I watched the hour long video about King John’s final journey. Unfortunately it is not the show I remember. I’ll watch the 1964 video later, but it is definitely not it either because that one is in color. Also I’m wondering if I’m taking bits of Time Team episodes and have created a composite show in my mind on this topic, that does not actually exist. Cheers.