SJA Checklist: The Eternity Trap

Crowds of people walking through London under alien influence: No. Though we do get crowds of alien-influenced people standing on a staircase in a stately home.
Tie-in with Doctor Who story: No, though it rips off "The Stone Tape" and "Sapphire and Steel" shamelessly.
Rani's Mum is annoying: Rani's Mum gets another break this week, along with Rani's Dad, Luke and K9. Casting department has definitely suffered a budget cut.
Star Wars reference: No.
Mobile phone as plot device: Yes-- of course everyone has to switch off their mobiles when entering the haunted house, as mobiles interfere with the ghosts or something.
Luke says something so daft that you have to wonder how he gets through life without being mercilessly bullied: Luke, as noted above, is absent-- but we do learn that he has mercilessly beat Rani's Dad at chess, and Rani's Dad is none too pleased.
K9 interprets a figurative English expression literally: No; there's no K9. Taking the role of guest annoying "smart" person and infodump machine this week is Toby, whose parents should have known that's a dangerous name to give any character in a nu-Who story, seeing as the last one got possessed by the devil and all.
Sonic lipstick: Check.
Wristwatch scanner: Check; Sarah uses it in episode 1 before bragging to Toby that hers is better than his.
One or more of Sarah's companions falling under alien influence: Yes, sort of-- it's Professor Rivers, actually, but she's a semi-regular.
Sarah and/or companions acts like a selfish cow: In spades. Sarah's recent encounter with the Doctor causes her to go into full Tennant mode, bragging continually and smugly to the guest stars about her space-and-time-travelling activities.

And I would also like to say that it really, really irritates me when I hear silly lines about scientists covering up paranormal activity because they "can't explain" it. In fact, scientists can explain paranormal activity-- it's just that the explanation is usually rather more boring and mundane than "ghosts exist."

On the guest star front, it seems Anthony Valentine is appearing in Coronation Street these days. I find this slightly depressing.