Support American Express for Plus / ISA / SIPP payments

I don’t see anywhere in the app and Freetrade’s help site that indicates what payment methods are supported for recurring monthly payments (i.e. for Plus / ISA / SIPP payments) - even the payment method change / update screen doesn’t indicate - but I’ve deduced through trying that Amex is not currently suppporting.

I would like to be able to use my Amex card to pay for Freetrade - is there any intention of introducing Amex as a payment method for recurring Plus / ISA / SIPP payments?