Hello, I am Keith, one of the experts on Jut Answer, and pleased to be able to help you with your question.
Current VAT Registration Threshold is, as I am sure you are aware, 83K in any one year.
You buy from Amazon Debit VAT 4-17, and Cost of Sales 20-82. You sell to the customer Credit VAT 4-17, Sales 20-82. In accounting terms the answer is the proverbial lemon.
I do hope that I have been of assistance.