Is it possible, that once a .GTM file has been created, to modify the settings at all? I have a number of mesh solutions that I wish to investigate (i.e. analyse the parameters), however, it appears that the .CMDB file, only saves the most recent settings.

Any help will be appreciated.

I'm not sure what parameters you would like to analyse, but for dimensional changes to geometric features, Design Xplorer will be useful.

Alternatively, you may need to generate individual mesh files and corresponding .def files and then run a batch run to generate a set of results.