I tried to open a Folder from my Backup and get the following message:
"The Lightroom catalog cannot be used because the parent folder “/Volumes/BACKUP/Backups.backupdb/Eion's New Macbook Pro/2019-07-19-164526/Macintosh HD/Users/eioncoulthard/Pictures/My Lightroom Photos/Highland Tour 2017” does not allow files to be created within it"
Can anyone advise how to fix. My permissions is set to "read and write"
This is probably a macOS limitation you will not be able to get around. The path shows that the folder is still within the Time Machine backup. But Apple locks down everything inside a Time Machine backup (Backups.backupdb). Other than Time Machine, no application can break that open for writing. This is to protect the integrity of the backup, especially for Time Machine backup volumes formatted as HFS+ (the older standard) where it is notoriously easy for those to get corrupted.
The solution is to copy whatever you want to use to a normal location outside of /Volumes/BACKUP/Backups.backupdb .