I did however find one cool thing in an unexpected place. In the pet section at poundland I found these fleece blankets with spider and bat designs:
I brought 4 - 2 bat and 2 spider ones. They are really quite small so I really want to make them into a patchwork throw. I already have a black fleece blanket and some leftover purple fleece (somewhere in a box...), so I just need to buy a small amount of white fleece fabric and then I will try be able to start stitching.
This is my design, please ignore the MS Paint drawing! The spotted bits are the pattern fleece blankets.
Hopefully it will be ready for next Halloween!