Using Fast IMG Unlocker resolved my issue, Thanks.

I did read that thread, I did not find an issue copying the map to the SD, except it was extremely slow using the Garmin device, i should have used a card reader.

Now that I have the Garmin Topo V3 map working, I am very disappointed in the detail of the map it is NOTHING like the screen shots Garmin show on their site, is it possible I am missing files which add the detail? or should I be looking at using OZTopo instead?

Any advice is greatly appreciated.