[dita]

Just tried again and generated a campaign. Selected a core force (two tank platoons) and was stll unable to delete them at this stage. Set the turns to two and played through scenario.

At the fix/expand core screen after battle one, I was then able to delete some core forces (removed one tank platoon) and added some infantry.

Looks like the core cannot be edited on the initial selection but can be at a later date (the interim "fix/expand" core screen

Not sure if it is helpful but I`ve attached the "in between" save games. One straight after the core selection, one after the mission and then one after changing the core force.