Yesterday I emptied my old XP computer, fitted a wireless adapter and gave it to a young relative. He's delighted but signal strength from the Homehub in the kitchen to his bedroom was very low.
After an hour the signal dropped out completely to the family's phones as well as his computer. There were plenty of signals from BT and TT neighbours but not from the kitchen, even when the phone was beside the HH. I concluded the HH was on the blink and phoned BT support.
The very helpful Muktash in India ran quickly through his script, tried change of channel etc and told me he could increase the power of the HH, and did so. Signal strength is now low but fully usable in the youngster's bedroom and the phones work all around the house. The home is rented so major mods are not possible.
Maybe the experts know about this but it was new to me. It might help somebody else with signal problems.