"Every driver must accept card and contactless payments and provide receipts for those payments upon request.

All taxis must have a fully working TfL-approved fixed card payment device fitted within the passenger compartment - a handheld-only device will not be sufficient to meet the licensing requirements. Any taxi found not to meet the requirement will be issued with an unfit notice, which will remain in place until the requirement is fulfilled and the vehicle is presented for inspection."

So it looks like either the story was a little old, or the cab was in violation of the rules.