A normal Fe atom has an electron arrangement of:
1s2 2s2 2p6 3s2 3p6 4s2 3d6
You're removing 2 electrons from it to generate the Fe2+ ion, which are removed from the 4s orbital first (this is always the case in transition chemistry - as far as A Level is concerned)
So the correct arrangement is
1s2 2s2 2p6 3s2 3p6 3d6.