Alright so that's very strange ...
Despite occurring on every single one of my devices regardless of the browser I use, indeed it turns out it was a semi-local issue, but it's a very strange such:
I cleared cache, tried different browsers etc but no matter what I did it wouldn't show the updated banner. Then I tried it on my phone, and as soon as I turned the wifi off it loaded fine.
Did a good bit of troubleshooting and it appears to be network related, even if I bypass the router and connect directly to the modem the 'old' banner would load instead of the new one. On any OTHER internet connection however (such as tethering from my phone), the new one loads just fine.