Following a tip from MFGF I've had another play with My Audi and Audi Connect and they've fixed it - pity they didn't tell anyone!!!

A few points to note:

1. I had to delete my old profile and create a new one to get the "My destinations" section to work - re-register the car with the VIN etc
2. When the MyAudi website starts up you may find it all in German if the language screen does not pop up - if so select "Landerauswahl" and go from there
3. MF pointed out that you can send a destination to the car (once your account and car are set up), directly from Google Maps by using the "More" link from the pin pop up window on google maps, you then select Car and Audi and enter your MyAudi ID and it sends it straight to the car and MyAudi. This is really rather good! When you go into the MyAudi website this destination also appears on the map!
4. When entering a destination on MyAudi, it took postcodes OK, but had trouble with house number and postcode - try it and see
5. Destinations entered either way actually work with the Nav system in the car, which they didn't back along when we all first tried it.

Sadly at my house we only get 2G mobile phone so it's all a bit slow, but I think it will be a great help when holiday planning, especially with continental destinations.

Also, I happened to notice that the area around the forward facing camera by the rear view mirror is obviously heated as it ripped through the ice on the screen - pity the whole screen isn't but Ford have a patent etc etc

Enjoy

Jon