Now that we're done with TAR 32, backtracking a little bit to TAR 31! (This double filming schedule is throwing me off a little.)
Found some tidbits at Dover Castle, which was part of the penultimate leg in England. Teams entered through the Constable's Gate and ran down to the WWI fire command post. Possibly designed to get teams tired/lost, since there's a much closer gate (Canon's Gate) involving less navigation and running.
Production originally planned to have the clue/task in the wartime tunnels, where Operation Dynamo was orchestrated to evacuate British troops out of Dunkirk in France. That didn't happen for some reason, and this was relocated to the command post instead. On a good day you'd have a great view of the Channel and the coast of France. There isn't that much space for a task though.
If there's a task I'm speculating it might be something to do with wartime communications? That seemed to be a key theme in both the tunnels and the command post.
Looks like the focus is more on World War history than the medieval side of Dover Castle.