I have made several changes. Here are some examples....
Ai more Aggresive (especially Maldonado and Grojean)
Hulkenburg better than Di Resta
Vergne better than Riccardo
Massa not so rubbish (I was fed up with him being so low down the grid)
Sauber better with Tyre wear.
Mclaren twice as likely for a mechanical failure.
Webber sightly more likely to have a mechanical failure.
THIS HAS NOW BEEN TESTED AND WORKS, PLEASE LEAVE COMMENTS