Im afraid this is more 1940s than AD40s
No chariots Involved, but Roman standards is a clue, in a way. I was thinking more of the symbol of the roman standards and what sort of locomotion the symbol used (too cryptic ?) you seem to have the area correct though
Would a map reference be helpfull, or another photo
This is close to the centre of Roman Britain and when AlanK said Magna Carta he was in the right ball Park