We may have accidently found a fix for this.
We;ve just upgraded the MSN Messenger on two of our Orange Bolds
(got it from here :
http://www.blackberry.com/devicesoft....do?code=wlm20)
And after the software was installed the BB Map icon is available (and working) on the home screen.
Now it may be a combinantion of having 4.6.0.167 OS installed, but it wasn't there before the WLM upgrade.