The hem is now done
I tried doing several rows of seed stitch below the edge of the cable band, but I just didn't like the look of it.
Instead, I have worked 1 row of knitting (actually just the row where I picked up all 190 stitches across the cable), then used a knit two together bind off on the WRONG side of the work to get this hem edge.
Part of the problem with the seed stitch was that when I started to bind it off, it looked like a ruffle below the cable band, definately NOT what I was going for! (my daughter is just not the ruffle type)
This edge I like. Using this bind off was new to me, and doing it from the wrong side was just serendipity, so as usual, my sweater knitting is a basically a "happening".
Now its on to picking up the stitches along the top edge and start knitting the body of the sweater.