There are a couple of small pulls on the back of the dress near the hem - see photos. No stretch. Lined. Length Approx 53” - I don’t know why the M&S says 36”, maybe they measure from the waist!

Please take a few minutes to compare the measurements shown in the photos with one of your own items to ensure a good fit. I currently have several similar size items listed, to view them go back a screen and scroll down to Seller’s Other Items, happy to combine postage.