Series 9 Episode 7 discussion

[KiKi]

I've just noticed two irritating things about this episode; sorry if they've been spotted before. When Ruth's Nokia phone is ringing at Deery's, and she's in the middle of screaming / shooting / shouting:

1 - Her phone is actually switched to silent and yet is ringing.
2 - Her phone network is 'Tesco'. I find it hard to believe that MI5 would sign up to Tesco as their mobile comms provider.