Thanks for the replies on this subject in various threads.
Finally I had to detach after messing around with an XML editor to see if I could access the newer URL through that way but no dice
Anyway I took 4 WU's that were completed but 'unreportable' and removed them from the projects folder before detaching. After detaching, while the GUI was giving 'wait a while ' messages I dropped them back into the projects folder and one of then immediately uploaded and updated and I receieved a credit increase. Of the other 3, one began to get crunched over again and the other two are waiting among the 4 more that the project subsequently downloaded.
If I must detach again for some reason, beforehand I will retain all the workunits in the projects folder whether done or not and dump them back in after the re-attachment.
If you still need to detach to change the URL- you might want to try this- seems it did no harm and preserved some units from a couple weeks in WU purgatory.....cc