I am in South England with a SMETS2 smart meter and an SKU2 Hub with an internal T2 antenna. The signal is intermittent with 4 lights on and off green includes WAN in position 2 and HAN in 4.
Outside the building there is a reliable Telephonica mobile signal. BUT I am being refused a T3 external antenna because it is claimed the signal is too weak.

Is there a way the I can buy and install a T3 antenna, run the cable through to the T2 antenna and boost the signal.

If this could work what antenna should I purchase.