Actually, I find the P4 in the opposite direction (towards Lewisham) awful in the morning, at least during term time. It is usually packed full of school kids, many of whom for some reason refuse to move down, even when asked. It is also really unreliable with large gaps between buses, much longer than the timetabled 10 - 12 minutes. I got sick of standing for ages at the stop only for one to sail past without stopping, despite there being loads of room at the back. So I now walk over to Stanstead road and get the 185 or 122 which generally works out ok. I contacted TFl about the overcrowding and they referred me to their Network Development Team, who apparently deal with comments about the capacity of a specific route. Have not heard anything back as yet. A single decker during peak times isn't really sufficient with the current timetable.