Windows 11 Slow Download

My set up is below:

Tenda Nova node with ethernet connection to the PC.

Upgraded my PC recently and now it appears that windows 11 is throttling my internet speeds to 1MB download on speedtest.net, never had this issue before on my old PC Windows 7/8. To resolve this, I have to restart my pc or network settings and its fine for 20 mins and then it all starts again. Does anyone know what could be causing this issue? I'm on Skybroadband 400MB and was easily achieving over 100MB download on my old PC.

I haven't seen any issue with the slowness, have a 25Mbps Wireless DSL service connected to my Gigabit Router and downloaded the 5.4GB .iso file yesterday AM using the MCT/Media Creation Tool and speeds ran 2.3Mbps to 3.2Mbps, pretty much normal.