Altering a FieldGroup within a Paragraph

Problem/Motivation

We are using Paragraphs very extensively in our site build and one of our Paragraph types uses a Field Group to display field values as follows...

We are trying to work quite which hook we need to implement in order to grab the value of the field_my_label field and use it to override the label for the Field group in the Display.

Can anyone point us in the right direction here as we have tried all sorts of approaches but can't seem to get there!

Thanks all.