If you want to extend your wireless network.
You can refer to the UG below.(Page 79-80)
http://www.tp-link.com/res/down/doc/TD-W8968_V4_UG.pdf

Hi, thank you for response.

I followed steps in UG.

I have reset it.
Plugged in cable, logged in from my PC to web admin panel.
Changed wifi channel to one of my Virgin: channel 11. Then set it to be bridge, selected my virgin router.

Next I was comparing signal strength in my garden with this router on and off. No difference in signal strength. :/

I am not sure if my mobile was actually getting correct signal. Should TD-W8968 be 'transparent'? Just passing signal without informing that it is on the way?
If this is how it should be this device is not extending wi-fi signal.
It is not being displayed in my 'Virgin Super Hub 2' as connected device too - so I think there may be something I am still missing. This would explain lack of improvement on signal strength in the garden.

Do I need to set up something else or this is it - no other options are possible?