[...] drones will carry items to Graemsay and Hoy where postal staff will complete their delivery routes.

Graemsay gets 2-5 ferries a day (assuming the passenger ferry can take mail), Hoy gets the same ferry, plus 3-6 a day at the other end of the island.

This feels similar to this experiment on North Ronaldsay, which already has 3 flights a day, which can deliver the mail. I think Carla (in the video) puts it well - there is the odd occasion where the mail has to be left till the next flight, due to the plane being overweight.

(Also, I don't see how this new trial is more of a "service" than the North Ronaldsay one, so the headline is kind of incorrect. Also, "Orkney has become the first location in the UK to have mail delivered by drone." is a complete lie, even thought they link the other article right below it.)

I'd be more interested seeing the delivery vans replaced with smaller electric vehicles. Usually when I get my mail delivered, it seems that the passenger seat is large enough to store most people's deliveries.