This sound IS the architypical sound of a neck pickup of a Les Paul and a Marshall. Have you ever plugged a Les Paul with PAF-type pickups in an old Marshall? This sound is what you get when you swith to the neck pickup. There ist absolutely no way to get even in the ballpark with the middle-position. If you have the chance of seeing Mark live, he does play it on the neck pickup as well. I have never seen him playing that song with middle position.
Garrincha, I think it's best to just post an image taken from the 1985 Wembley concert during Brothers in Arms performance. Try to find the PU position on your own. 'nuff said, I won't comment on the other statements.
[Blocked Image: http://www.wikpa.org/_files/mk-middle-position.jpg]