This is what I've done and it worked for me on my 2016 vRS:
Traffic Sign Assist Activation:
1. Control Unit 5F - Information
2. Adaptation
3. Car_Function_List_BAP_Gen2
4. traffic_sign_recognition_0x21 = Activated, then Green tick
5. Car_Function_Adaptions_Gen2
6. menu_display_road_sign_identification = Activated, then Green tick
7. menu_display_road_sign_identification_over_threshold_high = Activated, then Green tick
8. Control unit A5 (front / advance camera)
9. Security access - 20103
10. Control unit Long Coding
11. Byte 1
12. Bit 0 Activate - "01 Traffic Sign Recognition (FTE) active", then Green tick
13. Control unit 17 (Dashboard)
14. Control unit Long Coding
15. Byte 5
16. Bit 2 Activate, then Green tick
17. Display end of speed limit symbol in A5 adaptions
18. Control unit A5 (front / advance camera)
19. Adaptation
20. Display end of speed limit symbol
21. Importance to activate: Display valid additional signs
22. View Channel Valid suffix
23. Corresponding value: 00100111. (default was 100111)
Remember to select the green tick at each stage of the adaption, otherwise the changes you've made won't stick.