Continuity mistake: When Holmes finds Lestrade in the bar, Lestrade is seen putting his glass down, but in the next shot he's still holding the glass up. The items on the bar change around too, depending on the camera angle.
An Unnatural Arrangement - S2-E6
Continuity mistake: At the start, when The Woman first fires at the door the holes are quite dark and splintered. Then when she moves to pick up the phone the holes look far neater, like they've been drilled.
On the Line - S2-E9
Continuity mistake: When Holmes and Watson are arguing in the kitchen, Watson puts her mug and phone on the counter. A few times during the scene, the mug switches which side of the phone it's on. The first time it's plausible Watson moves it when off camera, but subsequent to that, we can see enough of Watson to tell she doesn't make enough movements to change the position of the mug.
Continuity mistake: When Cloe and Watson are talking and drinking tea in the kitchen, the positions of the cups and the teabag string change depending on the camera angle. Not just where on the placemat, but the orientation.
Continuity mistake: Watson came to Mycroft's place, spent the night and was awoken by Sherlock (this episode) the next day. Somehow she had a nightie and a brand new outfit. (00:00:05)
Answer: I'm the same person who asked this question. I discovered it was Molly Price whom I recognized from Third Watch.
Cathrine R
It should be noted Donna was Jim Fowkes‘ secretary. Donna killed Peter.
Bishop73