Thanks for the replies fellow quilters. I am using a DSM (a 1958 Kenmore to be exact!) and I did pin baste. I wondered if I pinned too far apart....probably did.
I also wondered if I should SID first. I guess I should have and I probably will in the future. (If I do that, I need to pin baste also right?) I also wondered if my choice of batting played a part here.
I chose not to quilt the borders because I can see there is way too much play in the fabric there to get it to lay flat. I did consider quilting straight lines from the FMQ area of the border to the edge, I guess that's what Tartan meant with "piano key stitching"? (goggled that term but didn't see what I thought it meant). I may add some quilting to the borders still.
All good info for the future. I make mistakes on every quilt but I learn something with each one too.