I thought let you know that I found a way to solve my problem. A friend pointed me to the QuadTone RIP product, so I gave that a shot and voila! no more bronzing, no more coloured halos and no more banded gadients in shading.
Seems to me that the Epson printer driver introduces too much color into the B&W printing process.
On a side note - I used Epson enhanced matte paper for this print and the Epson printer driver wouldn't let me use the "Advanced B&W"mode, even though the documentation said I could.
Anyway, I'm a QTR fan now! If only I can find some QTR Hahnemuhle profiles...