Theory:SJA television discontinuity and plot holes/Revenge of the Slitheen


 * No explanation is given for the absence of Kelsey Harper.
 * She might have moved school/house, or just simply stopped keeping in touch with Maria. Kelsey Harper wasen't intended to be series regular.


 * How does Mr Smith know of Abaddon, The Beast or the Macra?
 * Macra have appeared in Earth's past (during the classic series of Doctor Who), and seeing that Mr. Smith is an amazing super-knowledge 'Xylok, why not? Also, Abaddon and The Beast have existed before appearances in Doctor Who and Torchwood, so there is a chance he/it picked up information from the events.


 * The speed of light is still not enough for the effect of the Sun being drained to be instant, it would take days, if not weeks for the sun to "go out".
 * Maybe the Slitheen also turned out all light from the sun, thus causing light still travelling to us to also be turned off.


 * When Mr. Smith is showing them the American news channel down the info bar at the bottom it says 'thepacific ocean' instead of the 'The Pacific Ocean'.

It wasn't all drained at once. perhaps the sun had the most energy and was 'weak' to the tech and was absorbed first.
 * If the Slitheen's device absorbed all nearby energy, shouldn't the various types of energy (electrical, chemical, heat etc) in living organisms be absorbed too?


 * Mr. Smith brings up a world map before Sarah-Jane says it.
 * He might have been monitoring her brain patterns and predicted that she would ask for one.


 * When the Slitheen that was Janine is chasing Sarah Jane through a warehouse, the shadow of a camera can be seen on some cardboard boxes as it swings round.