Bootcamp "the startup disk cannot be partitioned or restored to a single partition"

Thanks for your speedy response Loner T...

Much of this worked until I got to the mergePartitions function... Here's what it came out with.

diskutil mergePartitions jhfs+ BCMP disk0s3 disk0s5

The chosen disk does not support resizing.

Do you wish to format instead? (y/N) y

Merging partitions into a new partition

Start partition: disk0s3 BOOTCAMP

Finish partition: disk0s5 Boot OS X

Merging partitions encountered error "Operation not permitted (1)".

The erase will not occur.

I then also re-ran the diskutil list function. Here's what come out.

diskutil list

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 1.0 TB disk0

1: EFI EFI 314.6 MB
disk0s1

2: Apple_APFS Container disk1 789.0 GB
disk0s2

3: Microsoft Basic Data BOOTCAMP 7.9 GB disk0s3

4: Apple_HFS BC2 203.1 GB
disk0s4

5: Apple_Boot Boot OS X 134.2 MB
disk0s5

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +789.0 GB
disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 118.6 GB
disk1s1

2: APFS Volume Preboot 23.1 MB disk1s2

3: APFS Volume Recovery 523.6 MB
disk1s3

4: APFS Volume VM 2.1 GB disk1s4

Would you happen to have any ideas on how to solve this please?

Well, this is weird... disk0s5 has disappeared... please see below how far I got with the command sequence.

Phillips-MacBook-Pro:~ phillipcurrie$ diskutil eraseVolume jhfs+ BC1 disk0s3

Started erase on disk0s3 BOOTCAMP

Unmounting disk

Erasing

Initialized /dev/rdisk0s3 as a 7 GB case-insensitive HFS Plus volume with a 8192k journal

Mounting disk

Finished erase on disk0s3 BC1

Phillips-MacBook-Pro:~ phillipcurrie$

Phillips-MacBook-Pro:~ phillipcurrie$ diskutil eraseVolume jhfs+ BC2 disk0s4

Started erase on disk0s4 BC2

Unmounting disk

Erasing

Initialized /dev/rdisk0s4 as a 189 GB case-insensitive HFS Plus volume with a 16384k journal

Mounting disk

Finished erase on disk0s4 BC2

Phillips-MacBook-Pro:~ phillipcurrie$

Phillips-MacBook-Pro:~ phillipcurrie$ diskutil eraseVolume jhfs+ BC3 disk0s5

Unable to find disk for disk0s5

Phillips-MacBook-Pro:~ phillipcurrie$

Phillips-MacBook-Pro:~ phillipcurrie$ diskutil list

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 1.0 TB disk0

1: EFI EFI 314.6 MB
disk0s1

2: Apple_APFS Container disk1 789.0 GB
disk0s2

3: Apple_HFS BC1 7.7 GB disk0s3

4: Apple_HFS BC2 203.1 GB
disk0s4

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +789.0 GB
disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 119.0 GB
disk1s1

2: APFS Volume Preboot 23.1 MB disk1s2

3: APFS Volume Recovery 523.6 MB
disk1s3

4: APFS Volume VM 2.1 GB disk1s4

Thank you so much Loner T, this solved my problem and I was able to restore the drive back to its original state. I'm greatly appreciative of your support.