flexable hoses
 

Just had a report from the Autocentre, my o/s flexible brake hose is perished! I've bought a new hose from Citroen for £11 but the Haynes book says I need a "brake spanner" is this a different from a normal spanner? as the nut on the fixed brake pipe seems to be a odd size (between 11 and 12mm) 11mm is too small and 12mm slips.
can anyone help?