Bassenthwaite's name is reckoned descended from, "in the old tongues", name meaning "the clearing of someone -- chieftain, or whatever -- called Bastun". Bastun thought to be an Anglo-French nickname or surname -- originally meaning "stick" (modern French baton); "thwaite" from the Old Norse thveit = clearing. I'd think that there can't be many British place-names hailing from French + Old Norse -- scholars of this subject more learned than me, may know otherwise. However -- what with the Norman Conquest: place-names coupling Norman French and Anglo-Saxon, are quite common. An example of this is Herstmonceux, East Sussex: from Anglo-Saxon hyrst = wooded hill; and the name of the Monceux family, lords of the manor there as at the 12th century.