The British names are all south of the Seven-Wash line. This may mark them as early or as due to Belgic name forming habits.
map list
Durovernum = Canterbury
Durobrivae = Rochester
Durolitum = Little London, Chigwell
Durocornovium = Wanborough
Durobrivae = Water Newton
Duroliponte = Cambridge
Durovigutum = Godmanchester

Unlocated
Durolevum = Kent?
Durocornovium = South-west
Durocintum = near Gloucester?

Unsure
Durocobrivis = Dunstable
*Duronum = Dorn (Wo)

There are eight names in France with "duro":

Domqueur, duro|icorregum Somme
Dormans duro|mann|ensis duro|mannus (horse pony) Marne
Dormelles duro|mello (hill) Seine et Marne
Drucat durcaptum duro|catu (battle) Somme

Durban duro|banno (horn, curve) Aude
Durban Ariege
Duban Gers
Durbans Lot

The northern group are from the lands of the Belgae and probably related to the British names. The southern group all linked to a "bend or curve" are suspicious.