I thought I would share a couple of finished pics with you since you were all so lovely consoling and commiserating with me over my spiral quilting trials. In the end, the wibbles in the spirals have had the edge taken off by a good old tumble in the washer and dryer and it's not quite as bad as I thought. I still would have preferred a smoother spiral but the quilt looks good nonetheless, I think.
This quilt is intended for a gentleman recipient and we hope it will provide some comfort to him and his wife at a worrying health-related time. Thank you to all of you who contributed wonky crosses blocks for us.
As an update to my questions re the guide bar on the quilting foot I have confirmed that the bar that came with my walking foot is indeed only intended for right of needle positioning. It is however possible to purchase an additional arm (which extends to 4.5" wide if wanted) which can be positioned either left or right of the foot. At another £13-15 on top of the £30 paid for the foot itself I'm not madly impressed but I probably will succumb at some point because I do love spiral quilting and really want to make it easier in future. It's also very handy for other guided quilting too.