Marnie Simpson can be seen in a club in series 1 even though she wasn't a member of the cast at this point.
Since series 11- Charlotte Crosby, Gary Beadle and Holly Hagan are the only 3 who have been apart of Geordie Shore since the beginning
Marnie Simpson chooses to leave Geordie Shore in series 11 after becoming engaged to her fiancé (now ex boyfriend). However, after their break up she's re-joins the cast in series 12
In series 11, Charlotte Crosby admits to Holly Hagan her purple hair was awful.
Scotty T has seen to appear in season 3 (Spring break in Cancun), even though he wasn't in Geordie Shore at the time.