Reference custom number list in Master Page

Hello,

I'm creating a report through a book -structure with multiple chapters and additional appendices as such:

1. First chapter
1.1 ----
1.2 ----
2. Second chapter
2.1 ----
2.2 ----
2.3 ----
3. Final chapter
Appendix A: A dataset
Appendix B: Another dataset
Appendix C: More datasets

The appendices can be quite lengthy, so on the Master page I want to create a footer referencing the Master page. E.g. 

My massive report - Appendix A: A dataset

I have been able to call "A dataset" in my master through text variables, but what I am unable to pull off is inserting the 'Appendix #' part for whatever appendix it is on. Can anybody tell me how I can obtain the paragraph number for a running header (text variable) or should I use some different way to let the footer follow the appendix numbering?

Your help is appreciated