"Hi David,
Thank you for your query regarding the security updates on your LG G5,
I have looked in to this for you and due to the size of the updates LG will only release these updates when they are neccessary as these will take up storage space on your phone. Since Novemeber 2016 (when your last update was released) there have been no security risks so an update has not been needed, the Vodafone patch you are seeing will have been released by Vodafone and not from LG directly. A security patch will be released when there is the need for one, as there are no security risks there is no need for a security patch to be released.
Kind regards
John
LG Electronics UK Help desk"
No need for security updates but the rest of the world is getting them...hmm.