Good to know, I haven't bothered updating to the latest I will wait for the new macOS and see if that fixes it. Out of interest are you running a Macbook Pro 15inch late 2013?
Yep, that's the exact machine I'm running. I took it to the Apple store and they tested all the hardware and found nothing wrong - it's definitely an OS software bug. Looks like they didn't test the new wifi software for that model properly.
By the way, I tried installing the beta for High Sierra and it didn't fix the issue for me, although it's probably still running the same wifi software as the previous version.