Hey Dannyk90,
I just tested what you are reporting and was not able to replicate your issue. I copied the set up you are using and added this widget to a blueprint. I tested it within Screen space and World space just to make sure the inconsistencies were not within those differences.
Below is how I set up the test. Try and replicate what I have here to see if it resolves your issue.
Widget Set Up
Widget in Blueprint Rendered in World Space
Let me know what you discover.
Regards,