John, it's not exceptional, it's called Dyscalculia. Public knowledge of it is probably as poor as it was of dyslexia 30 years ago.
Obviously things will progress as they will regardless but it would be nice of there was some recognition that for a section of the public such changes are more difficult than for others, through no fault of their own.
Maybe listing them in the FRA calendar in both imperial and metric?? Failing that hubby says he will draw me up a conversion chart listing the converted distances against each other