But aren't the SVLANS /CVLAN's shared by lots of EU's that would likely be with different ISP's , in which case it wouldn't be what has so far been unique to Plusnet customers, apart from a few cases earlier on that the cause was identified by AAISP as it affected customers regardless of ISP Also a customer changing endpoints via an isp gateway hop wouldn't also change the SLVAN/Cvlan that they where on would they ?
It IMO is the quantity bandwidth that they are buying from BT not being sufficient (running a large percentage of their links hot) which is probably not helped by the traffic plusnet management which could be causing all sorts of odd issues making it harder to identify the underlying cause ,
It's like some 12 months or more ago, the customers saw the peak time latency hump or excess jitter, again single stream throughput was affected as was the upstream, but not as severely, people complained plusnet a short time later reported that more capacity had been added , a short time ( days ) things improved for a few months then would return again, Plusnet has in particularly during the past 12mths has gained a lot more customers
They have increased the number of BNG's (gateways) but by customers hopping from gateway to gateway until they get connected to a less saturated endpoint which sees line speed throughput restored ,and some times latency as well, goes a long way in proving that it's something with the internal networking ( DPI traffic management ) that plusnet control or the capacity that it buys from BT is not suficient