It seems that the issue reared its head as a result of my "erroneous" assumption that
\book { Page layout stuff for front page } \bookpart { Header & music } \bookpart { Header & music } Was a way to go. Although this has worked over the years it doesn't today. If I just use \bookpart for each section all is well. My trap was finding something that worked and using that as a template.. I have just tried another old file and that too has failed, so possibly a recent minor change somewhere in Lily,Fresco,or Windows has highlighted my original sin. There is no profit in trying to find the reason. Regards Peter