Originally Posted by
Batterseabluesky
Thanks Brian, have just finally got through - it turns out it is covered because my original purchase that led to the voucher was on the platinum. I wouldn't have assumed that so thanks for prompting!
(However it wouldn't have been if not purchased on the platinum)
Amex Plat policy is super flexible, if the merchant does not accept Amex then you are still covered. They covered my 12k trip when they didnt accept Amex.