I'm definitely with Flying Lawyer on this one. There must be 10,000 fuel tankers driving the roads of Britain each one of which would make a better bomb than 2 tons of flimsy aluminium.
So you take your battery out - I bet you'd put it back smartish if a terr had a gun to your wife and kids heads at home.
Get real folks!
Good intelligence and covert skullduggery from the professionals is the only way to deal with terrorists, aided, of course, by an alert public who may spot the dodgy vehicle/ flat rental/ equipment purchases and tell Special Branch.