Hiya Jo,
I'd agree with everything PA said, especially on the ATC Scenario! The way I was told to play it was make up your mind what you would do, do it, and when the Interviewer presents another way to do it, agree with it, but stick to your guns!
It shows that your open to other ideas etc etc.
Also, on the Computer tests, I know a lot of people who have thought they have crashed and burned (me included!) on them! They drag on a bit, so just ' keep the heid!'
If u want any other info. get in touch!
Good Luck!
Gary