"Freeview lite" as mentioned above. Your transmitter is just a relay from other transmitters. Shocking really. Whoever owns the transmitters now (not BBC) apparently don't want to sort to it out.
ok. just looked at your local transmitter.
It appears to have BBC2, Babestation+1 and QVC if the wind is blowing in the right direction.
It's what known as a "freeview lite transmitter"
I'm surprised by the lack of freeview devices that integrate with tablets. There are still a few on the market that look like USB sticks but take a standard aerial connection.
Effectively a tiny freeview box, they used to work seamlessly with Windows Media Centre before Microsoft stopped...