Hi Loner T,
good to know, followed the instructions to remove this partition, and rebuild, this is the output.
TobiMBPR:~ Toblerone$ diskutil eraseVolume free free disk0s3
Started erase on disk0s3 (Recovery HD)
Unmounting disk
Finished erase on disk0
TobiMBPR:~ Toblerone$ diskutil apfs resizeContainer disk1 0g
Started APFS operation
Aligning grow delta to 208,314,753,024 bytes and targeting a new physical store size of 1,000,345,825,280 bytes
Determined the maximum size for the targeted physical store of this APFS Container to be 1,000,344,797,184 bytes
Resizing APFS Container designated by APFS Container Reference disk1
The specific APFS Physical Store being resized is disk0s2
Verifying storage system
Using live mode
Performing fsck_apfs -n -x -l /dev/disk0s2
Checking the container superblock
Checking the EFI jumpstart record
Checking the space manager
Checking the space manager free queue trees
Checking the object map
Checking volume
Checking the APFS volume superblock
Checking the object map
Checking the snapshot metadata tree
Checking the snapshot metadata
Checking snapshot 1 of 2 (com.apple.TimeMachine.2021-07-05-114107.local)
Checking snapshot 2 of 2 (com.apple.TimeMachine.2021-07-05-124237.local)
Checking the extent ref tree
Checking the fsroot tree
Checking volume
Checking the APFS volume superblock
Checking the object map
Checking the snapshot metadata tree
Checking the snapshot metadata
Checking the extent ref tree
Checking the fsroot tree
Checking volume
Checking the APFS volume superblock
Checking the object map
Checking the snapshot metadata tree
Checking the snapshot metadata
Checking the extent ref tree
Checking the fsroot tree
Checking volume
Checking the APFS volume superblock
Checking the object map
Checking the snapshot metadata tree
Checking the snapshot metadata
Checking the extent ref tree
Checking the fsroot tree
Checking volume
Checking the APFS volume superblock
Checking the object map
Checking the snapshot metadata tree
Checking the snapshot metadata
Checking snapshot 1 of 1 (com.apple.os.update-F8CC686BD994CAC58E0A525C64B2C9D6329887202C9FA5AC86D15A7994507C67)
Checking the extent ref tree
Checking the fsroot tree
Checking the file extent tree
Checking volume
Checking the APFS volume superblock
Checking the object map
Checking the snapshot metadata tree
Checking the snapshot metadata
Checking the extent ref tree
Checking the fsroot tree
Verifying allocated space
The volume /dev/disk0s2 appears to be OK
Storage system check exit code is 0
Growing APFS Physical Store disk0s2 from 792,031,072,256 to 1,000,345,825,280 bytes
Modifying partition map
Growing APFS data structures
Finished APFS operation
TobiMBPR:~ Toblerone$
Storage now shows i have 318GB available as free storage, so this could have very well done the trick? unless there is something in the above output that looks concerning?