Bulk Changing Product Tax Codes (PTC)

Hi, these would seem like a fairly simple thing to change, but seemingly not and I’m pulling my hair out with this now, as Amazon support don’t seem to comprehend my problem.

We list thousands of products via a 3rd Party ERP system, however our system does not support ‘PRODUCT TAX CODES’ and so every product we have listed has been set with the standard product tax code which is set on our account, ie it applies 20% VAT to every product. This is fine, but there are a percentage of products we sell that are tax exempt, for example books. (New Code to apply should be ‘A_BOOKS_GEN’)

I have tried to download an Inventory File in order to bulk update the ‘product tax code’ but there are a few issues with this. Firstly we list to multiple categories so its impossible to download a single file where we can mass/bulk update all these SKU codes in 1 file.

Secondly all of the Inventory Download File samples I have downloaded so far, don’t even contain the ‘PRODUCT_TAX_CODE’ field.

I followed a suggestion from the Amazon USA forum which is a few years old, so I suspect is out dated… download a Custom Inventory Report with ASIN, SKU and PRODUCT TAX CODE fields. Amend this file and re-upload… all seemed to be going well until I came to upload it and it failed, due to not having the correct ‘Amazon Header Row’ in the file.

ERROR
The file’s header row is missing or invalid. The header row is for Amazon use only and must not be modified or deleted. To correct this error, download the template again from seller Help and use that new copy, or insert the correct header row directly above the column headings in your existing file.\

So I’m at a loss on how to move forwards with this, Can anyone please advise because Amazon support are not helping me at all.

Thanks