What is there to say about this episode...
I will admit this episode made me laugh on a personal level since at my day job right now we're having issues with storage of camera footage. I like Sam being computer-competent again but establishing a nationwide network and server farm to store thousands of hours of footage? That's something modern governments are struggling with right now - much less a bunch of folks stashed in a WW2-esque bunker. Maybe if Charlie was still around... I mean the show had made her into a magical IT fairy anyway.
Oh wait! She is around again now isn't she?? I stand corrected - laughter withdrawn.
I also appreciated the episode taking an effort to give explanations for the djinn being different from what we had seen before. Simple little touches - a single line of dialog even - is usually all these things require to work. A little effort goes a long way for the audience.