I have a cunning plan:
Tell your missus that you have heard on WW that there is a planned demonstration at *Manchester Road. Explain that you'd better set off a little bit earlier than normal. When you get to college along relatively demonstration-free roads look puzzled and say, "Here's a pound for a brew, you go in and use the time to read through your class notes in the cafe." She'll be happy, you'll be happy, kids get a coke when they get to football (Call it hush money!) Bob then becomes your proverbial uncle!
* Insert nearest road name applicable.
Genius