First I cannot believe and that is I am way down on Vitamin "D". That is the sunshine vitamin and if it is not raining too hard or not too cold I am always out in the garden.
This is very surprising to me, since you live in Bali. Oh, no, wait a second, you live in England.
Seriously, I've been told that where we live (latitude lower than yours), we won't get much vitamin D from the sun. Also, it's rare that I go outside without being pretty covered up (for the temperature).
This is an EXCELLENT site concerning diabetes:
http://www.bloodsugar101.com/