Historic Cities is a joint project of the Historic Cities Center of the Department
of Geography, the Hebrew University of Jerusalem and the Jewish National and University Library. Its website has a good number of
scanned historic maps of mostly European cities, together with selected links to other similar maps and information on historic cities.
The UK maps dont show windmills, but I checked a good selection of likely continental European cities (such as Antwerp, Brugge, Amsterdam)
and all show a good number of windmills.
Maps of Historic Cities