Calamity Jen - S1-E2
Continuity mistake: Near the end of the episode, Roy is helping Jen push her shoes on. While he's pushing one shoe on, you can see Jen has her shoe on her left foot. Two shots later, she is completely barefoot and the shoes are nowhere in sight. After Denholm uses the stress machine on her in her office, she walks out with both her shoes on.
Calamity Jen - S1-E2
Continuity mistake: When the stress management therapist opens the suitcase containing the "stress machine", you can see an electrode on each side of the suitcase. In the next shot, both electrodes have moved to one side.
Answer: It's a joke on the "118" numbers in the UK. 118 numbers were used for directory enquiries and adverts for them on TV always tried to give a way to easily remember one for a particular company. The fake ad in the show takes it to the extreme. People in the UK do not use "911", the point of the joke was that Roy had forgotten "999" while saying it was easy to remember.