Export BLOB field from SQL Server to file on disk

ExportBlobToFile.sql

-- because I keep having to do this at odd times and I keep having to look it up

use master
go

EXEC sp_configure 'show advanced options', 1
GO

Reconfigure
go

EXEC sp_configure 'xp_cmdshell', 1
GO

Reconfigure
go

/*********** REMEMBER TO TURN OFF THE show 'advanced options' and 'xp_cmdshell' afterwards! ***********/

use MyDatabaseName

-- SQL Server export image

DECLARE  @Command NVARCHAR(4000)

DECLARE @DBServer NVARCHAR(100) = 'localhost\sqlexpress'

-- Keep the command on ONE SINGLE LINE
SET @Command = 'bcp "SELECT [file_field] FROM MyDatabaseName.dbo.attachments where attachment_id = 12345" queryout "C:\temp\test.pdf" -T -n -S'+@DBServer

-- This will export the file, but the file will appear corrupted if you try and open it. 
-- This is because the first 16 bytes are used to indicate the length of the file (they're a 
-- left-over from the SQL database binary stream), the bcp command doesn't strip them off.
-- Delete those first 16 bytes using a hex editor (or even Notepad++), save the file, and you 
-- should then be able to open it.

PRINT @Command -- debugging

EXEC xp_cmdshell @Command

GO

/*********** TURN ON THE show advanced options and xp_cmdshell afterwards, but do it in reverse :) ***********/

use master
go

EXEC sp_configure 'xp_cmdshell', 0
GO

Reconfigure
go

EXEC sp_configure 'show advanced options', 0
GO

Reconfigure
go

Hi there. I've tried to do this on a pdf file but I can't get it to open. I've tried to remove those 16 bytes but the file is still corrupt.
Is there any way to prevent BCP to include those bytes? Thanks!