In the same room you would have full signal unless you have a 50 inch thick metal cage around you and all your devices at all times.
The hub is faulty or the devices in use are faulty. Get the hub replaced.
There isn't a router I have used with better range and I've had a good 20 in my time.
All tests demonstrate it's better than sky talktalk and virgins hubs for range.
I pickup my 2.4ghz signal 2 houses down in their living room & it works.
What version have you got, A or B and what firmware is it using?
I know our Smart Hub - Type A is stronger than our HH4, no questions about it, but ours is located in our front living room where our ONT is located and when I go in the back of our house and the signal on 2.4GHz is near none and it doesn't even see the 5GHz band from there.
For us to get a good signal throughout our home I will have to install another Wi-Fi Access Point at the back of our home.
We are not the only one that has this issue, next door has the same issue and had to install another Wi-Fi Access Point for the back of theirs.
So at the end of the day it all depends on how many walls the signal has to go through, and if in a large house with loads of walls there will be issues.
BTBroadband - Infinity 4 - 310Mbps (down), 31Mbps (up)