Thanks Richard
Sorry about the long silence - various distractions.
I am about to have a go with your Perl script, and will report back.
Do you know anything about the German site that is now providing Illustrator downloads (sadly, only of Germany) - www.flosm.de/ai - and which seems an excellent model? I’ve had a go with it and the resulting file opened in AI but various aspects of the scale of the document were weird (the type, in particular, was disappearingly small although nominally huge)
Cheers