Its no mystery, as Evil One says its Mark Doyle - toured in 83 also and has a solo career - google him
The young guitarist during promised land is George Borowski I think - the guitar tech
http://en.wikipedia.org/wiki/George_Borowski
As in guitar George on Sultans of Swing by Dire straits. If that isn't him, he certainly has appeared on stage with Meat - that US TV performance of promised land from 81 for example