I used to hate that journey too. Oh the days of Uni! The P13 is just a bad a route and service especially at the early time of the last bus. Not ideal if you're seeing a late movie in Streatham!
The 12 can also be a nightmare around waterloo/westminster. Took me 2 hours once from the Plough to Piccadilly... made me late for the theatre grrrrrr! I have noticed the 176 in the evenings (from say 8pm) to be more frequent travel through ED lately. Maybe Arriva have more drivers at the Norwood Garage these days ;-)
They certainly are scary late night at the weekend. One particular journey zoomed from penge to Kings before I knew it... I wanted to get off on LL lol :-$
Two of my furry ickle monsters have demonstrated the love/hate relationship of marmite... one absolutely adores it the other pulled funny faces after licking my toast, ran away and then threw up :-| the silly moo!