Thanks Rich, I will take note of that. So here is the script for my own solution. It requires no third party unzip tools.
Include the script below at the start of the batch file to create the function, and then to call the function, the command is...
cscript /B j_unzip.vbs zip_file_name_goes_here.zip
Here is the script to add to the top...
REM Changing working folder back to current directory for Vista & 7 compatibility
%~d0
CD %~dp0
REM Folder changed
REM This script upzip's files...
> j_unzip.vbs ECHO '
>> j_unzip.vbs ECHO ' UnZip a file script
>> j_unzip.vbs ECHO '
>> j_unzip.vbs ECHO ' It's a mess, I know!!!
>> j_unzip.vbs ECHO '
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO ' Dim ArgObj, var1, var2
>> j_unzip.vbs ECHO Set ArgObj = WScript.Arguments
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO If (Wscript.Arguments.Count ^> 0) Then
>> j_unzip.vbs ECHO. var1 = ArgObj(0)
>> j_unzip.vbs ECHO Else
>> j_unzip.vbs ECHO. var1 = ""
>> j_unzip.vbs ECHO End if
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO If var1 = "" then
>> j_unzip.vbs ECHO. strFileZIP = "example.zip"
>> j_unzip.vbs ECHO Else
>> j_unzip.vbs ECHO. strFileZIP = var1
>> j_unzip.vbs ECHO End if
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO 'The location of the zip file.
>> j_unzip.vbs ECHO REM Set WshShell = CreateObject("Wscript.Shell")
>> j_unzip.vbs ECHO REM CurDir = WshShell.ExpandEnvironmentStrings("%%cd%%")
>> j_unzip.vbs ECHO Dim sCurPath
>> j_unzip.vbs ECHO sCurPath = CreateObject("Scripting.FileSystemObject").GetAbsolutePathName(".")
>> j_unzip.vbs ECHO strZipFile = sCurPath ^& "\" ^& strFileZIP
>> j_unzip.vbs ECHO 'The folder the contents should be extracted to.
>> j_unzip.vbs ECHO outFolder = sCurPath ^& "\"
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO. WScript.Echo ( "Extracting file " ^& strFileZIP)
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO Set objShell = CreateObject( "Shell.Application" )
>> j_unzip.vbs ECHO Set objSource = objShell.NameSpace(strZipFile).Items()
>> j_unzip.vbs ECHO Set objTarget = objShell.NameSpace(outFolder)
>> j_unzip.vbs ECHO intOptions = 256
>> j_unzip.vbs ECHO objTarget.CopyHere objSource, intOptions
>> j_unzip.vbs ECHO.
>> j_unzip.vbs ECHO. WScript.Echo ( "Extracted." )
>> j_unzip.vbs ECHO.