Annnnnd then i go to page 72 of the BT forum thread and see this, which gives me hope but also makes me want to wear my monitor as a bracelet ,
"Hey guys. I thought I would update the thread as I have finally managed to fix the issue for my setup after weeks of searching.
I recently upgraded to a Netgear Nighthawk XR300 and previously owned another Nighthawk model. While searching the internet for other people experiencing lag spikes during gaming, I found forum posts outlining the same issue with Plusnet, EE and some other ISP's in the USA.
I found some information regarding the Nighthawk OS (DumaOS) and a new feature in the QOS settings called anti-buffer bloat. You can read about this here.
Anyway, I looked through my Netgear OS last night and found that by default, the feature was set to 'never'
I switched this to 'always' as recommended by other forum posts and this has completely solved the ping spike issue. I also tweaked some of the QOS settings to prioritise my gaming set up.
If you are experiencing ping spikes and have a Nighthawk router, definitely try this and this is most likely the cause of the issue. If you dont own a Nighthawk router then buying one is likely to solve the issue.
Check the article out and give it some consideration."