Finally got up n running, then discovered that one of the files was failing with a "550 - not a plain file" the helpful instructions here say
Although it appears in the DPM namespace, the file doesn't physically exist on disk anymore. You should un-register the file from the namespace, to avoid this inconsistency.
Well, that'd be good if they gave a hint as to how to do so. "dpns-rm" didn't seem to work as planned.
On the plus side, it appears our bandwith INTO glasgow is ~650Mb/s shame the outgoing peaked at ~250Mb/s though.