Yes – it did work!
Thank you very much. It also helped me understand the plugin-friendly framework into the bargain.
Julian
I think I have answered my own question.
I modified the $expires value /bb-includes/pluggable.php from time() + 604800 to 0.
This appears to have done the trick.
I don’t know if this is technically correct way to do it, however, as I will now need to remember this modification if I overwrite the files with an update. Should I have written a little plug-in to achieve this?
Thanks. I had overlooked the bb-admin directory!