It has been many years since I have done any crewel. I bought a few kits
and the material was always linen. It was always bone/ecru. old/Maureen
Here in the USA, the fabric used for cross stitching is called Aida cloth. I suppose it would be the same for crewel work, too. I have used a bone/ecru cotton muslin fabric that worked well for machine embroidery cross stitch designs! Much cheaper than the Aida fabric.
Hugs, Angel