However, I made a determined effort and put the bodice back together again, added hooks and loops to the centre front, sewed in the sleeves and the wings, then tackled the skirt. This was an interesting problem - originally it was a 3 width piece of fabric draped over a drum or wheel farthingale, and pleated at its edge to make this sort of shape, although not quite so formalised.
What I was aiming for this time was something more like this.
However, I did not want to cut off the spare fabric. Eventually, I folded the fabric to give a reasonable length, flat pleated it to fit the waistband, sometimes several pleats thick, and whip stitched it to the top of the waistband. (I just hope it fits under the bodice.) I also stabstitched the back of the bodice to the top of the waistband, as the original back was a little short, and it gave nearly an inch extra in length.
As I say, I hope it all works as there was no opportunity to have another fitting. There is a small time lapse before S. wears it, so if necessary (I hope not) there is time to sort small problems. I will post better pictures of the before dress once I have them, and pictures of the altered dress as soon as I have those.
And now it is back to the tantalisingly close finish of the Diana dress, a pair of gloves for a friend, and all sorts of bits and pieces. I have a lovely length of grey cotton/linen to make into a skirt and trousers, so there might be something modern for me in the mix.