Thanks everyone, especially Brenda for the quotation from Singer Sewing (1969), a copy of which is almost certainly on my shelves, but I didn't think to look in there.
I'm pretty sure my small bits are cotton, they certainly don't feel like modern polycotton, which I suspect has a smaller proportion of cotton than when it first came about.
I am rather larger now than when I bought the Liberty print, and 5ft 10. There might just be enough to make me a shirt, but certainly not Pjs or even a nightie. Somewhere I have got a chart that converts yardage between widths. I must look for it (or Google for one) and see. Perhaps wrenkins is right that sundresses with matching hat and knickers would eat into it. My notes say that it cost £19.96, it seems crazy that you can't get a metre for that now.