The vat component of at price if vat is charged at 20% is not 20% of the sale price but 16.67%

A product with a value of 100 € will have vat of 20€ added total sales price 120€ the refund is 20/120 = 16.67%

Normally the global blue paper work States very clearly the vat component in the sales price and shows their huge commission and the final refund you will receive.

Never had an issue getting a refund from the uk.. Just the form stamped by customs and place in letter box at T5