Night buses aren't that bad at all. You'll get 1 or 2 days where at certain time's you'll have a few people on there that have been out on the razz, even then they confine themselves to the back of the bus and fall asleep. You can get to Waterloo on a night bus in good time from every corner of London. They are usually faster than you expect too, during weekdays they fly from the suburbs to central!
Being a biker myself, the last thing you want is to do an early shift (Which by all accounts is a nice ride into work) finish at around 2-3pm and have to fight the traffic back out and get home in one big stress. I avoid riding to work where possible but sometimes it has to be done.