Hello,

I believe I've found what's causing our problem, hopefully this may
help someone else experiencing something similar.

I was running the procedure from a Form button on the worksheet -
changed it to an Active-X button, and now everything works fine -
repeated testing appears to confirm the 'fix'. However, although it's
a non-issue in our situation, it still fails if run from the Ribbon
(Developer Macros Macro name) - which makes me slightly uneasy.

Perhaps someone can offer an explanation for this.

Regards,

Dave