I thought about what you had written whilst traveling to and from my appointment. On returning, I modified my original code, tested it and posted an update.

There were no replies when I started to compose my post. I got distracted midway and, when I did post, I saw ikegami had replied; however, I had to rush off for $work and didn't really look at it closely.

Thanks for your further explanation. Unfortunately, the vaccine is already taking effect and the code is just spinning around before me. Looks like another weekend of being completely ga-ga: probably best to revisit this in a few days.