I've got GNR the week before and English Half the week after. That weekend I've got to squeeze my last 20 miler in or I'd have done it! 
I've got visions now of Mrs SGQ standing there, telling the person next to her "that's my son, you know - he does this for fun!" 
I know it's a toughie, but they'll be others who will have more info than me. Good luck!