You may be looking at the modelers version of the Osprey addition. I am speaking about the reference version. These books along with photos generally have a few artist renderings. I know one of the rendering shows the wire skirts. These were on very late versions of the Mk IV. I will check when I get home to see if any photos show the wire skirts and I will let you know what page it's on.
ISBN 1-85532-843-7 Maybe your book is newer.
Anyways, learned something new.