Newbie on this forum, so please go easy

I have been using Backup & Replication for some time, it backs up my home server (just a test bench, really) every night to an external hard drive. It keeps 4 days of backups, and my understanding is, it will over-write the oldest every night.
Long story short, I suffered drive failure (I lost my RAID) and experienced data loss on my DATA drive. My OS Drive was separate, and wasn't affected. The Server still boots and acts normally, for all intensive purposes. I have since repaired the RAID, added new drives and it's working at an OS level. I can read, write, etc as I did before.
I am trying to restore the data from VEEAM's backup (which is on the external hard drive) both at a file level and a volume level. Problem is, NEITHER are recognized.
When I go onto the external hard drive through Windows Explorer (it's a 2TB drive) I can see 2 files, both VEEAM. One is a config file and one is a backup file. The backup file is 1.7TB, so it obviously contains data. I cannot for the life of me, work out why the application won't recognise it's own files.
IS THERE something I am DOING WRONG???
Please help in any way, literally happy to try anything, but I need this data. It's my only copy, and I really hope it's just something silly I am doing wrong.
Many thanks in advance!