Hello Graham. Yes, it is a router. Actually, my long axis is Y (front to back) and X is left to right. When I look at Mach 3 the table view shows machine zero at the front left, but my machine zeros at the back right. I am not in my shop at the moment, so I'll have to check in the morning, but I'm pretty sure that my numbers are opposite of yours. Soft Max for Y is 48, for X is 24 and Z is zero. Soft Min is 0, 0, and -4 respectively.
When I am watching the machine run in the window in Mach 3, X and Y are running backwards, but the machine is physically running correctly. If i jog it with the keyboard, the keys accurately match the machine movements. I would think that if the down arrow moves the gantry towards me, then M3 knows which direction the machine is going, but it is reverse in the view in M3.
I will change my settings tomorrow and post back the results.