Quick update:
It turns out that I don't have the virgin hub after all and must have sent it back when I switched over to BT.
I also ended up disabling the BT wifi hotspots that are on by default on the smart hub and since then I have had quite a several long sessions of Half-Life Alyx and finally managed to complete it (wow what an experience!) with no network spikes.
Half-Life Alyx is very hungry and it has to be running with steamvr in the background which doesn't help with performance. I find that if I log out and login again, it resets my vram usage to around 500-600mb and when I play HLA for long sessions, it is a smooth experience with no performance hitches if I relog.
I now try to avoid using steamvr altogether and try to force either Openxr via VDXR or Oculus runtime in games as they perform much better than steamvr on the quest 2 and together with FFR, I get massive performance uplifts with no picture degradation on my vr games!
So I am now fairly happy with the performance of VD and hardly get any more network lag spikes.
Thank you for everyone's help and contribution