I understand virgins network under intense load at the moment due to covid 19 but I've been experiencing this issue long before covid 19 started. I though it was my google wifi that had the issue but I've recently bought asus zen xt8 mesh wifi and it's doing the same thing. It happens after 6PM where I do a speed test I have 0mbps download and 0mbps upload for about 5 minutes then it shoot back up to 350mbps 36mbps upload. I've posted network log below.
Your pre errors are going through the roof but your modem is dealing with them but this would cause lag in response at times. I would make sure all your connections from where the cable enters your property to the splitternif you have one and the back of any equipment is as tight ad you can get by finger and then power cycle your modem to clear the log.
Andy, Field Technician working from home.
Here to help! I'm a technician helping out whilst working from home. Find out more
I've managed to sort the connection issue it was an issue with the router cable after thorough investigation. I replaced with another cable and all is fine now 🙂. I also swapped attenuator with another from an old installation and the power levels are now spot on must of been poor one. Now there's also no microstuttering so my sons happy.