Cory,
Thanks, I think I’ve solved it. Somehow the database had got “changed” – not sure how. the database file prefixes on the web server had 2 uppercase characters but the local ones were all lower case (otherwise identical) – no idea how / why they were different – or why it hadn’t been an issue before…. So I sorted that (along with the related entries in PHP Admin). This may be why Duplicator seemed to have issues clearing down the installation files on the web server each time?
I also updated the text-based links on the web version (not that many) and all now seems to work ok. I’ve tried installing to the web server again (to make sure) and it all worked fine. Just a warning that my QiQ web hosting is using MariaDB but my local version is running MySQL. It never used to flag that so perhaps there has been a change at QiQ.
Anyway, thanks for your help.