Mr. Finn. As there is no direct shuttle bus between Hangzhou airport and Shanghai, I think the fastest way is to take the D train. After you walk out the Hangzhou airport, take a taxi or shuttle bus to the railway station directly. Buy the tickets of D5670 14:55/ 16:18. If you cannot catch this train, try the next one D5676 15:55/17:27. If you take the latter one, you only have one hour left when your train stops at the Shanghai South Railway Station. Then get a taxi directly. Time is just enough. Good luck to you!