As this is currently inaccessible, is there another way of accessing the backup data?
Nope
You need a running copy of Backupexec to get at the data stored in the BKF files
I suppose that if you have a spare desktop, you could install BackupExec on that, then create a B2D folder that points to the share on the network, then inventory and catalog each BKF file, but that could get into a lot of work real fast