If it is a poor connection into the property, then the speed problems should be apparent on all floors, although if you're seeing a maximum of 250 on the ground floor with a 500 connection, then that may be an indication of problems - a modern wifi device such as any premium smartphone should be able to hit 450-550 adjacent to the hub.
Connect to the hub by clicking on this link http://192.168.0.1/ That should pull up the log in page for the hub. But don't log in, just click on the link "Check router status" That'll bring up a window with five tabs. Open the Downstream tab. Select all the text (Ctrl-A if using a keyboard), copy it (Ctrl-C), then paste it (Ctrl-V) into a reply here as text, not screensots. Post that, do the same for the Upstream and Network log. You'll get an error message when you post the Network log, just click on "post" a second time. Then we can check for any obvious problems with power, noise or error counts on the connection.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks