The Inverkeithing option is starting to look pretty doable
http://www.worldtaximeter.com/edinbu.../inverkeithing
Supposed to be be around £22 and 20 minutes
Leave Dundee at 8:45, arrive at Inverkeithing at 9:33
As the journey shouldn't take longer than 30 minutes that seems plenty to get the 11:20am departure even with some (hopefully not excessive) rail and road delays. It's a couple of pounds cheaper to get to Inverkeithing than to Central Edinburgh and with the £3.50 NOT being paid for the airport bus trip, cost of getting the taxi from here is only about £15. A good price for over an hour of extra kip.
I knew Inverkeithing was a connection point but hadn't appreciated its proximity to Edinburgh or EDI.
BRILLIANT! Thanks!!!