Providing right to work proof when visa is in process, need information about ongoing application reference number

[Tash87]

My partners tier 2 dependant visa is still in process and the previous leave to remain has expired. In order to check the right to work the Employer needs to validate it using the following link
https://www.gov.uk/employee-immigration ... ent-status

Under link it states provide either home office reference number or case ID. We have none but once in the application instead of using the word home office reference number it asks reference number of on going application. Are these two the same? It’s very confusing.

[Tash87]

So I’ve done some research and got to know that we can provide UAN number to employer to do right to work check.
Now my only question is that there were two dependant applications together my partner and our kid.
The UAN appears as xxxx-xxxx-xxxx-xxxx on my partners application and on our child’s it appears as xxxx-xxxx-xxxx-xxxx/01

Now on the appointment confirmation the UAN of my partner is xxxx-xxxx-xxxx-xxxx/00 which UAN should be provided for right to work with or without /00 or it makes no difference?
Thanks