http://www.johnchaple.co.uk/romanroad.htm

That is quite an interesting read though the suggestion that people
assume it was built to cross London Bridge is quite puzzling. Even
Wikipedia says it is pretty much accepted the route into the City via
London Bridge is not the original one and the 1903 document it links
to talks about it being likely to go to the Thorney Island area (just
west of Westminster Bridge) to use the well known ford there.

Perhaps the same technique should be tried out to find evidence for
the route of Ermine Street where it is lost through Edmonton.