The Ravenna Cosmography

The definitive source for the British Section of the Ravenna Cosmography is an article published in Archaeologia 93 1-50 (1949) by I.A.Richmond and O.G.S.Crawford.  Here are scans of its photographs of the three surviving manuscripts:-

  -   From the Vatican Library: Page1, Page2, Page3, Page4.
  -   From the Paris Biblioteque National: Page1, Page2, Page3.
  -   From the Basel University Library: Page1, Page2, Page3, Page4.
(Numbers added to help you find individual names are not present on the original manuscripts)

And the names read from those photos are listed here.

A law change in 1996 probably brought back into copyright (of the Society of Antiquaries) any original text written by Richmond and Crawford or their adviser Ifor Williams.  If you want to read that, and cannot get it via a library, you can either pay money to Cambridge University Press or ask here for it.