Re: I's the overal experience....
"a chap in a white van, clip board and hiviz could cause more damage in regards fatalities and anarchy."
Terrorism is about making a showy point. You're absolutely right that a subtle approach can cause far more damage, but the intention of a terrorist is to draw as much attention as possible to the cause he or she is promoting.
Their attacks aren't usually thought through all that well in any case. The 7/7 bombers managed to disrupt at least 5 million people, shut down public transport and got everyone moving on foot, but had they used a single car bomb as well, the entire city would have been in complete panic. It was the scenario that was running through my mind whilst (unsucessfully) telling the gf to stay put and get the hell off the streets. I'm quite sure it's the disaster scenario that was running through the minds of the police and security services as well.