Name The Year: Demolition began in NYC for new permanent headquarters of the UN.?

Questions

Robins Nest and George and Mildred were spin offs from which sit com?

Which London theatre house is built on the site of a well once famous for its medicinal properties?

By what more familiar title is the First Lord of the Treasury better known?

In post war fashion who was responsible for the New Look?

What or where is Europa?