This is who I contacted about my incident (called, didn't write):
London Buses Customer Service Centre, 84 Eccleston Square, London, SW1V 1PX
phone: 0845 300 7000
This is the TfL complaints policy ... [url]http://origin.tfl.gov.uk/assets/downloads/corporate/London-Buses-complaints-and-feedback-policy.pdf[/url]
or you could contact the bus' garage directly. Use this site to find the garage ... http://www.londonbusroutes.net/garages.htm
Hope this helps.