It's great that you have a grandson that is playing and you are helping him out. I don't want to rip you off. I of course wish to save some cost.
For your duplicates of Chaos Legions cards. I believe there are 34 cards. Checking other under advanced options for duplicates. I'll offer 8.5 hive for these 34 cards.
Three other cards I am interested in are:
Bortus
Mother Khala
Mitica Headhunter
I'll offer you 25 Hive for these three cards.
You can choose one, both or neither of these offers.
!CTP