Mine was seemingly only getting about 30 - 40Mbit/s just now (On an 80Mbit/s sync) but then again I've been playing with different routers over the last couple days so it's quite possible it was the router I have on the line at the moment.
Reconnecting PPP fixed it.
Would reconnecting PPP feasibly be likely to fix a problem with the router you are using?
It probably was P/N but given i'd been playing with my network setup recently and didn't have time to test properly I don't want to say 100% that it's them as I can't be sure.
Current setup is as follows
Plusnet connects to a RB750 running routerOS, I was also playing with VRRP between it and an RB450G with the RB450G being the master, the default route on the RB450G points at the VM cable line so in order to force the traffic path to use plusnet I triggered a Mangle rule in the firewall to redirect traffic via an alternate routing table.
This means that the traffic path is RB450G > RB750 > Plusnet and also the RB750 isn't really an ideal router for an FTTC line as it's a little under powered for that (Depending on which features were being used).
I'd normally be using an EdgeRouter Lite but there seems to be a problem with the HW acceleration and the load-balancer, especially if you start using PBR to force certain traffic to a line and the device has a problem dealing with 150 + 80M and Policy routing connections in software routing mode.
Currently got a Linksys LRT224 on order, in a completely different class compared to the routers above, infact it's almost primitive in comparison but claims to do 900Mbit/s across the Nat and load balance, so it sounds like they've got the LB accelerated... Interestingly it seems to be a slower single core version of the CPU in the edgerouter (Cavium octeon)