Removing etopo21 from device

Data manager, 'clear maps' button at the bottom of the panel.

Thanks for that.

I came across this issue when I deleted the Topo 21 maps from my iPad and installed the Topo 23 maps.The amount of data the topo 23 maps should take up on a device is about 8.5 gig as shown in Data Manager but in my case the topo 23 maps were taking up 13gig on my iPad when I first installed the complete Topo 23 package.
This meant somewhere in the software the topo 21 maps had not been completely deleted even after I had deleted them to free up..somewhere 6gig was being retained..it had to be gone as I was getting "space error messages" when I was trying to install the complete Topo 23 map package.
It can be a pain for users who have "limited storage space" on the iPad...my has 32gig.
So to resolve this I did a complete uninstall of the Traveller App on the iPad and confirmed this by checking the iPad "systems" storage, to see that the Traveller App was no longer on the iPad, yes, a PIA..but in my particular situation, it was necessary.
Then I did a re instal of the Traveller App (found in the App Store under my previous purchases) and then appropriate Topo 23 packages.
When the full reinstall was completed the Topo 23 Data Manager showed space of the full package was 8.5 gig and not the 13gig as before.
Problem solved.