Hi again (and so much thanks for your help), sorry you can ignore that last snapshot. I'd been experimenting with a netduma router which is supposed to prioritise gaming traffic, I've just forgotten to switch the wifi back to the homehub. And yes I agree the sourceforge results all seemed a bit extreme.
Is there anything I can do about rate limiting of ICMP? I've no idea what that means, or if it happens on both my homehub and nighthawk routers. I'm quite confident my ethernet cables are ok, they're all cat 6a Duronic and well reviewed on amazon, 25m being the longest one.