In British slang, to give someone the "Spanish archer" is to give them the elbow ("El bow"). That is, to reject, fire or release them.
Some of the characters have had their names, genders or races changed from those that appeared in the book by Peter James. Vosper was a blonde Brummie, Kit Bishop was called Brian, Katya Bishop was called Katie, Sophie Carrington was called Harrington, Joan Talbot was named Treadwell and Roberta Vernon was actually named Robert.
Jon Simm and Arthur Darvill have both starred in Dr Who