After three fire incidents in January on London buses, I wrote to TfL with safety concerns and asking for clarification. Of the three fires that took place, two were on electric buses and one was on a hybrid bus.
In their response, they said that "neither TfL nor our bus operators would run an unsafe network." Moreover, "there is nothing to suggest that the battery was at fault in any of these vehicles." They are still investigating the incidents further.
No buses or bus routes in Kensington were affected by the fires.