Under the new legislation, any business selling goods or services electronically must charge VAT in the country of the consumer. They then pay the VAT to the tax authorities in their counrty of domicile, and the tax authorities distribute it back to those in the country where the service was consumed.
There are some exceptions, but AW clearly is captured by the rules. This is the HMRC guidance:
Digital portals, platforms, gateways and marketplaces
If you supply e-services to consumers through an internet portal, gateway or marketplace, you need to determine whether you are making the supply to the consumer or to the platform operator. If the platform operator identifies you as the seller but sets the general terms and conditions, or authorises payment, or handles delivery/download of the digital service, the platform is considered to be supplying the consumer. They are therefore responsible for accounting for the VAT payment that is charged to the consumer.
Digital platforms and accounting for VAT
If you operate a digital platform through which third parties sell e-services you are liable to account for the VAT on those sales unless every one of the following conditions are met:
the digital platform and everyone else involved in the supply must identify who the supplier is in their contractual arrangements
the invoice, bill or sales receipt must identify that supplier and the service supplied
the digital platform must not authorise the charge to the consumer
the digital platform must not authorise the delivery
the digital platform must not set the general terms and conditions of the sale
If you do not meet all of these conditions, you must treat the sales of third party e-services as if they were your own and declare the VAT due.
If you do meet these conditions, the responsibility for accounting for the VAT moves back to the person who supplied you and you are providing intermediary services to that person.
So eBay, for example, meets all the conditions for exemption. AW does not.