Hi Tim, thanks very much - details on wireshark and how to use it can be found here.

We managed to borrow a different router from a friend and have tried that out. It seems to have solved some other problems and I'm keeping an eye on how the VPN performance goes for the rest of this week. So far today it is OK but we shall see if that continues.

Will report back soon!

Tim

VPN performance seems fine now. No sign of lag all morning. Even on good days in the past couple of weeks there have been occasional small lag spikes. Guess it must have been the router.