Replacing the watch unfortunately dosen't make any difference...
We either wait for Garmin to sort the issue....meaning they remake the map smaller in storage space or you can delete the inbuilt maps in the watch and their associated files like I did...after talking with product support....
then install the new maps.
I then took off the side of Europe I didn't need....which left 2.7 gig for my other personal maps.
All under the instruction of Garmin Uk.
There was a post here also that someone was kind enough to explain how to do it.....Ill see if I can find it....