Misc: Played banjo on Young's "Old Man"?

Questions

In Greek mythology who was the twin brother of Castor?

Who lived in Ivor the Engines boiler?

Who said of Margaet Thatcher" I wouldnt say she is open minded on the middle east,so much as empty headed"?

Where was the Grand National run between 1916 and 1918?

What nationality was the artist Magritte?