Bt homespot 600 issues

[Remikp04]

Basically, on wifi I get 210megabits/s download with my virgin media router. However, I got a bt homespot 600 extender recently and I have that plugged into the router with the ethernet cable it came with (i think it's a cat 5e) and upstairs i got a ethernet cable going from my other one to the PC (cat 5e) and they're plugged directly into the wall sockets, and they supposedly work by sending the internet through the wall sockets so yeah. And I only get 80megabits/s download, but same upload. Any tips on how to make it better? The internet is still good but it's just the fact I could be getting a lot better internet than I am right now.