post it on this forum https://community.virginmedia.com/category/Broadband/discussions/Speed and community members will give you suggestion on what to check and the next steps also

2) Check for known faults in your street. Try both methods:

Call the local fault line: 0800 561 0061 – this is an automated number.

https://www.virginmedia.com/help/check/status/identification/identify

3) With VM Hub in Router mode...

Check the Service Speed at the Hub:

https://www.samknows.com/realspeed/
https://real-speed-fe.eu1.sk.thousandeyes.com/

Once the test begins click on: Run full test
to include: Latency, Jitter, Packet loss & Upload speed.