If your website doesn’t work on my screen, it’s not my fault … it’s yours

I came across the website for totrain.co.uk. 

Here’s how their ‘about us’ page looked on my PC’s screen via Firefox.

In case you can’t read it clearly, the words above the blank space say:
 
                         Places We’ve Worked
 
Hmmm?

The Blank of England? [thank you Spike Milligan]
 
I checked it out on Microsoft Edge and there was an interactive map. I’m guessing it’s the computer science behind the ‘interactive’ bit that’s causing the problem.
 
Two points:
1    Would the Firefox-using potential customer have opened up Microsoft Edge?
2    This organization [it would seem] offers e-learning. That is, learning via the Internet. And they can’t make their website work properly.

Hmmm [again]