This was lying in the grass by the towpath only a short distance from where I was standing when taking the picture in the previous post.
The size of the skull and the prominent brow ridges indicate it belonged to a fox.
There were no signs of any other bones. There were no signs of the skull either when I went back a few days later. It had most likely been cleared away by the British Waterways trimming and mowing crew who had been along in the meantime.