Re: 'Security' questions?
"My bank tends to ask questions like "You recently charged £49.75 to your account, can you remember what it was for?" - well, probably not but I'd guess a tank of petrol maybe? Not perfect but it's better than the other options."
When reading articles like this one - and posts like yours in particular - I am usually reminded of this - followed up here and here.
What this says is that the "you charged £49.75 to your account..." type of security question isn't a lot of use if they then guide you to the answer.