After a reboot of my router following a doubling of latency, I was unable to connect to thinkbroadband.com. Tracert showed the problem appeared to be at the hand over point from Plusnet to lonap-gw1.thdo.ncuk.net. Only thinkbroadband.com was affected. Other sites worked fine.
After hop four which was inside the PN system, everything was timing out. Two further router reboots resolved the problem.
4 28 ms 28 ms 28 ms xe-5-3-0.ptw-cr02.plus.net [22.214.171.124]
Timed out from here until another couple of router reboots.
5 31 ms 29 ms 29 ms lonap-gw1.thdo.ncuk.net [126.96.36.199]
Doubling of latency, and dropping IP Profile are probably not related, but ongoing problems.