Well the best way to get to the Astoria from London Victoria would be taking bus number 8 from the bus station outside Victoria tube station getting out at Tottenham Cout Road. From there, there are just 2 seconds walking.
Another way to go from the airport to Central london is: from Stansted get the Stansted Express to Liverpool Street and from there take the tube (central line ) to Tottenham Court Road. Up to you choose any option. anything else i am here to help
