Two different schools were used between series one and two due to availability.
Steve tries to woo Agnes by boasting about his role in Lord of the Rings, saying you can see him for a second in the Extended Edition DVD. In real life, two of his onscreen fellows appeared in The Lord of the Rings: The Return of the King (2003): Paul McLaughlin, who plays Principal Dasent, appeared briefly as a Captain of the Guard, and Thomas Robins was strangled to death by Smeagol after unearthing the Ring of Power.