Despite my best intentions of re-doing the site 10 months ago, clearly it never actually progressed. In the mean time, new versions of WordPress have arrived (which this site now runs from), and advances in adding themes have been made possible.
The good news is that the core of WordPress now supports galleries; the bad news is that it means each and every previous post that contained an image needs to be edited with all the images re-uploaded to take advantage of them. I’ll be doing this whilst I also do the templates and themes.