Safari 9.0.1: Website loads on one machine, but not another (typeError)

Machines: Post 2012 iMacs

OS Version on both machines: El Capitan 10.11.1

Safari Version on both machines: 9.0.1 (11601.2.7.2)

Hi all

I'm having problems getting a website (https://beinsportsconnect.net/) to load. The background colour appears, but no elements load. As shown here in a side-comparison with Firefox...

Trying to access the site on Safari on my work machine, with the same versions of OS and Safari, works perfectly. The problem only occurs on my home machine.

I only tend to use the site on various weekends, so unfortunately I cant pinpoint the time when this started.

I have done the basics such as emptying the cache, deleting web data and there are no extensions in use. I've followed every instruction here: http://www.macissues.com/2015/06/22/how-to-fully-reset-safari-on-your-mac/ but it still fails to load.

When viewing the error console, this error appears: TypeError: Attempted to assign to readonly property. ring.js:349, which looks like the below:

When viewing 'ring.js' in the network window, it shows this:

I've completely run out of ideas now, and googling the problems doesn't find anything specific to this.

If anyone has any ideas, I'd really appreciate hearing them. The site loads fine on Firefox, but the streaming quality just isn't as good when connected to the TV.

Thanks for reading this far