However, it has been suggested before (so "you read it first hear" seems
a bit implausible).

Very interesting, and you may have stumbled across some interesting evidence
of the past. However I'm afraid I have to agree about reading it here first.

A TV programme- probably Time Team, although if not something like it- dug
up part of the grounds of Lambeth Palace to try to find the ford over the
Thames which was the means by which Watling Street crossed to what's now
Westminster.

But anyway, if ths is real evidence of the route in urban parts of London
it's an endevour to be applauded.