Misc: The city of Sheffield stands on the River Sheaf; and on which other, major, river?

Questions

Who was the ruthless chief pig in Orwell's Animal Farm?

What was the first name of the Reverebd Varah, the founder of the Samaritans?

What is another name for a tomato?

A person putting a lot of effort into a task is said to be using?

What is the occupation of Mary Poppins?