Sorry for the delay in getting back to you on this, I've been busy.
Here's what I saw a few moments ago when I looked at the site using a browser that hadn't viewed the site before on a system I've just had built:
prntscr.com/6x19xv
I then uploaded the following file to overwrite the one on the server:
../templates/rt_hexeris/css-compiled/thirdparty-k2.css
And I see this:
prntscr.com/6x1apg
No idea what's happening or why but it's frustrating as hell.