This is great. I loved the bit in the supermarket at the beginning. In fact, the story stayed in the supermarket for quite a while, which was good as I love those sort of 'ordinary' settings where extroadinary things start happening.
Sarah Jane is noticing strange behaviour from one of the staff, only to find it is, in fact, Clyde, who is in turn noticing strange behaviour from an old man, one of Sarah's neighbours. I found this to be the best part of the story, better than the settings in the middle, (the museum where Luke was working) and the end (car scrapyard place).
What I like about this too is that you get good music and sound effects, not all the time, but at parts in the reading, which greatly adds to the atmosphere. (In some of the earlier stories on audio, there was no music or sound effects, just a straight read).
Elisabeth Sladen is always good to listen to, she does a good job of conveying the other characters' voices and personalities, especially Clyde.
Other good audios in the series are: Ghost House, and White Wolf. The rest are not so good, but still worth a listen if you like Sarah Jane, as I do. I just wish they would do a full cast audio drama of the Sarah Jane Adventures as well, as has been done with Torchwood. But even if they don't, I look forward to some more SJ audios raad by Elisabeth as she does a great job with the reading. Add to that the music, much to enjoy all round.