These guys aren't the doctors of recent fried crispyness, but the group that tried a follow on attack on 7/21/2005 after the tube bombings on 7/7/2005. It looks like from the surveillance of the "mastermind" buying the ingredients before the 7/7 bombing that they were an independent cell that wasn't necessarily connected or directly inspired by the 7/7 attack. I always guessed that the failed 7/21 attack was because they were using TATP from the same batch as the 7/7 bombs, but that it had gone stale. I guessed wrong.
ok thanks, i misunderstood, got the wrong group. but that makes the latest group even dumber. they should have learned from the previous group that they needed somebody skilled in basic math to prepare their bombs. It is a good thing they are stupid.