British intelligence is at least considering the questions raised in the article linked to in this previous post.

Regarding the July 7 attackers (not the subsequent ones):

They bought roundtrip train tickets and paid for long-term parking – two of the details that are prompting the intelligence community to question if the four London bombers intended to die.

Associated Press: Did London Bombers Know They Would Die?

Those who disagree with the ‘not suicide’ hypothesis suggest the bombers were being cautious to avoid suspicion.

Home Politics Was It Suicide? (Part 2)