How to delete backup set on local drive that is not listed in Norton 360 Backup sets

Hi folks, I have Norton 360 Ver 22.22.11.12 on my Windows 11 Laptop. I use Norton 360 to backup my laptop to a local drive. The local Drive shows 4 backup sets in the N360 Backup folder. I can only see 3 when I Manage Backups in N360.

1. How can I see which sub-folder in the N360 Backup folder on the local backup drive is for which Backup Set?

2. Im sure 1 of the backup sets on the local drive, are for old PCs I no longer use. As I cannot see it in the N360 App, How do I delete the unwanted backup sets, once I know which is which - as per Q1 above?

Thanks for your help folks.