If they only find that 1000 feet of this road existed, I’d put in a guess that it was a market area that was paved over.
Not that surprising. Don’t forget that there was considerable contact between Britain and the Romans before the conquest. In fact, that was one of the reasons for the conquest. Julius Caesar gave it a shot twice, but he was motivated more by the fact that British Celts were giving assistance to the Gauls he was trying to subdue. Claudius not only wanted a conquest to cement his tenuous position as emperor, there were those tin mines…
How did he know about the tin mines? There was quite a bit of trade before the conquest.
And nobody has a patent on cobblestones. Anybody could have come up with that.