ACCA P2 Group SFP – Change in structure – Example 5

I have two questions. 1. Well calculating Goodwill, don’t you have to separate GW attributed to Parent and NCI? For jones in this question pre acq value was 110 so wouldn;t parent GW be 120-(110×90%)= 21? Sub 13-(110×10%)=2 Thus total GW of 23 as shown in the question? 2. Also when valuing the 20% sold, I’m confused on whether it should be [120+the attributable GW+ post acg retained earning (90% x10)}x20% Then use this as the increase in value of NCI Please advise