Question for NordVPN / WireGuard Users

I haven't needed to touch my NordVPN WireGuard peer for over a year, but recently I have started to see very slow upload rates (as in circa 5 Mbit/s).

I tried switching peer to another NordVPN server and it helped for a bit but not for long. I'm not sure what's going on but am hoping others can comment. This is with an RT3200 on 22.03. There could well be other factors at play such as my ISP applying 'traffic maintenance' or something else I am not aware of.

Anyway, any thoughts/experiences from NordVPN / WireGuard users would be much appreciated.

This could well be some form of 'traffic manangement' from Vodafone UK.