Thanks for your reply.
Signal Detection:
Watching BBC1 HD:
CH22, 482000Khz, 8Mhz, 32K, 1/128 (DVB-T2)
Strength 50-52%
Quality 100%
Watching BBC News HD:
Ch55, 746000Khz, 8Mhz, 32K, 1/16 (DVB-T2)
Strength 50-52%
Quality: Fluctuates widely from 5%-100%, but mostly below 20%
I'm in Tewkesbury...