The 33 (or, in the Harleian Manuscripts, 28) cities listed, and possible translations of their names can be found in the Giles* translation here (this varies in the online versions because some of the English names given didn't appear in the earlier Giles*, specifically: 3,4,8,9,10,11,13,21,29,30,32,33). Gildas (see Other Works) notes that Britain in his time is famous for its 28 cities, though doesn't list them. Ptolemy, in the 2nd C, lists 58 in his Geographike hyphegesis ("Guide to Geography": see Other Works), though what counted as a city can be judged by the inclusion of Ilkley (Olicana: though see Rivet and Smith*)...

As mentioned in note 6, the attribution of modern names to 'Dark Age' locations is notoriously tricky. There is, for example, a recent alternative attempt by Ford*, (though note that it is hard to say what sources it is based on).