Can someone please help me get this working. I have it at least going to the shopping cart but it says basket is empty http://www.watersportsproducts.com/store2/test.htm

You need to check each form element individually as opposed to checking them as a collective as you're trying to do.

In other words:

var select1 = frm.elements["Select_1"].selectedIndex;  // notice how I did an underscore instead of a space.  It's good practice. 
if (select1 < 1) { 
    // Do jah thing.
    return false;
}

Repeate for steps 2 and 3.