Hi,
powerline adapers do rely on the house hold wiring, and in some cases if this is causing issues with the transmission of the signal across your mains circuits, there is nothing specifically we can do to resolve this.
I do use my youview box wirelesly. This is not something that talktlk provide, but I use a usb powered wireless nano router configured as an access point and this works really well.
I picked this up from amazon for £16. Link below.
Karl