Montana 700 Map Nightmare

My M700i shipped with DEM base Map, TopoActive Europe and CN Europe. I did a software update to 8.4 and also did a map update on both. Since then DEM base map has disappeared and I can't get Topo Active and CN Europe to load to the unit as it appears they are too large. I reduced the coverage area and still does not work. It strikes me that a 16GB drive on the unit is simply to small.

I brought the unit with also TOPO GB 1:50 on a card which is only 8GB.

Spoke to Garmin who say install the TopoActive on a SD card even though their website says you cant do this! Every time I try to load it to the card it fails.

Any ideas?