Phil, the logs you refer to, and the boats in Yorkshire, are river vessels not seafaring craft.
There is a difference, as the Dover boat, being designed to travel out to high sea, is known to have docked in South West Britain, not far from Cornwall where the copper mines were.
Dover's vessels were engaged in big-time commerce sailing the seas around Britain and crossing over to Gaul and back.
Information about the oldest sea vessel can be found online, and it is definitely Dover's! I personally made sure of this!
