Thanks for the leads.
Yes it's quite messy doing it this way but it's all there is at this stage.
I propose that perhaps Arduino, who have the software, add this following functionality to the IDE.
Instead of locking the boards menu to a few simple options, allow each user to enter the 8 bit device they are using. The IDE then updates the boards.txt and adds the new Core functions to the Cores Folder - much easier to do once the IDE is the handler, not the user.
It may be possible to also add 16 and 32 bit AVR devices and perhaps even ARM cores once the IDE has evolved.
There is a need for this type of IDE rather than using more complicated and cumbersome types such as Studio6, Atmel32 etc.
For most work the Arduino IDE is fine, but it really does need to have this new 'Core' choice functionality to make it a versatile IDE.
Perhaps Arduino engineers could think about that - it will make this IDE quite powerful.