Could I inquire as to the lack of rivers in Britain? Everywhere else on your fine map seems well endowed with rivers, but Britain does not. From what I can tell none of the major waterways in Britain, such as the Severn, the Thames and the Trent, have been included.

They may not be as long or globally significant as mainland rivers, but they were of tactical and strategic importance here, and since you are going for accuracy, I'd have thought you'd have included them. Since this is a work in progress (and a very good one at that) I hope you can fix this little 'error'.