Had to reword my post as I made an incorrect assumption that my upload was being throttled artificially by a person or automated system, but it's more like theres something with the router when you put some upload rate through it, or the router sees uploading as a potential attack., perhaps some settings just need to be adjusted on it to accommodate big uploads.
Conversely reaching my download speed limit has never throttled my download and required a rebooting of the router, I don't understand why uploading at 5mbps or so (nowhere near my limit) is causing the router problems.
My download is always 70mbps+ and Upload always 18mbps+ In the attached picture you can see that my download hasn't become throttled so there is nothing wrong with the line/hardware but If I upload a livestream at a high upload (but still far, far below 18mbps) the PC I was using becomes throttled by the router to 3mbps-and-under upload until I reboot the router.
Rebooting the PC does nothing, I'm still stuck at 3mbps-and-under. Unless I reboot the router that's where it will sit, so there definately isn't a problem with the PC.
Adding another device and doing a speed test will get me a much more normal upload rate. The router is just targeting the PC that did the livestream for a low locked 3mps-and-under upload rate (until the router is restarted)
I'm using the "TalkTalk Super Router" HG635. Hardware Version G.101 Software version v1.14t
If specific router problems and settings are outside of the scope of the help that can be provided please let me know so that I can think about purchasing a diffrent router if this one just dies under the pressure of uploading, but it seems really silly is that is the case.
Quick picture of my Routers page
Could you first of all try switching the router off for at least 30 minutes then switch back on and check to see if the same thing happens again, please let us know how you get on