Smart - thanks Michael! He also said that since my machine came from Sweden it's going to have Swedish ROMs. Oh well, they're socketed so replacement with English ones should be easy.
Finally got round to making the 'grey cable' up for the machines using a DIN plug, half an RCA audio lead and some speaker cable, and as you can see at least one of the machines is happy! The Swedish ROMs appear to be for the keyboard encoding and chargen only, so that's good intit.