You should be able to ask for additional ones, KC... maybe. BT allows up to three.
We previously had some sort of signal booster which went through the wiring (?!?

I don't really know...) in addition to three BT white discs. But even with both, it was hit and miss upstairs. The new set up gives us just as good a speed upstairs as downstairs, so we are pleased. (But still annoyed that they lied to us and there is a new offer for £10 less with the 'discs' (/squares!) Can't help it's a bit of a scam/money not quite for old rope for them but certainly very lucrative. And does it really cost them more to give you more data once you have the necessary hardware?
Meanwhile in France... our satellite (current ADSL - as they call broadband there - set up) provider has been taken over (again) and are now offering more data with a rolling contract. We can cancel then pay £30 to start it again. Sounds a lot but still cheaper than paying £35 a month when we are rarely there in more than two months in the year. (If we did this, we'd have to make sure we don't go in a week that bridges the start of the new 'month'.) Question is, how much data do we need to do our jobs, and maybe watch some TV? I can't find out from my account online. BT doesn't think we need to know because we have unlimited data. Will have to investigate. (They must have a record surely.)
Our data on the current tariff has been doubled to 60GB/month but we could get up to 150GB.
Speed can be 24MB but often drops.
My neighbour switched to Virgin a couple of years ago (before you could get full fibre with BT, on our street) and he says it's ok, but a poor signal in the back room (he blamed the fish tank, but theirs is the mirror of our house so I suspect just the thick walls) and for some reason they can't get Netflix to work.