I spotted this in Primark the week before I had my surgery and it’s great to put over any clothes for an extra warm layer. It’s a lightweight, squared-off fringed shawl, in black or pale grey, and I think it cost £8. It’s basically one width of fabric straight down the back, and two half-widths down the front (no shoulder seam). So it’s open at the front - nothing to go over the head.
Sounds good Charlotte, my surgery was late spring so no shawls needed…but I have to say that what you are describing sounds ideal now the weather is so cold.