Windows 7 and Firefox 19.0.2 here.
And
I see the pop-ups referred to! Aha!
Well, let's don the deerstalker, light the pipe, take a look through the magnifying glass and peek under the bonnet...
(Some time later, back in Baker Street)
- Frames, Doctor Watson. Invented in 1996 and now deprecated for years!
- Applets too. The pop-ups ... ummm, "pop up" when the page loads. It's because our Firefoxes (but not RMH's) are asking us whether we want to let the applets run or not. It's a safety issue: these are ok (the applets provide a link to the gallery images) but there are newer technologies around today which'd do the job better: and without popping a thing.
- Biggest horror: the website is nowhere near HTML5/CSS3 standards. Indeed, there's no Cascading Stylesheet at all. It's rather as if the main site was brewed up ten years ago, and almost smells of something churned out by an old Microsoft program.

Martin - I'm always on the forum, hardly ever look at the main site: but
it needs a make-over.
I'd suggest something in WordPress: port all the content to a WordPress platform. It would make your/administrator's jobs of updating and uploading new articles super-easy (being a CMS), and you could tweak design and layout to your heart's content once done.
Andy, the web developer.