Thanks so much to you both.
I will speak to my parents in the next few days and let them know your advice.
My Dad in particular not only has diabetes but chronic M.E. His condition seems to be getting worse rather than better and to me, this makes sense if it is Candida that is worsening the condition. In fact I recently read a book by Erica White who suggests that it can often be Candida that brings about this condition as well.
I think the problem stems from a large number of Health Professionals who simply do not have the knowledge about this condition to make an infomed decision to provide advice to their patients.
Once again though, thanks for the help!