in this set up

a1--a2-a3--a4
b1--b2-b3--b4
c1--c2-c3--c4
d1--d2-d3--d4

isn't it better to take for example;
C1 adult and infant
c2 solo child
d1 adult

this way adults in c1 and d2 with cranking of the neck can see the solo child? with the partition in place - c3 is not affected

I am doing BOM-LHR with kids for the first time and have opted for a1/a2/b1/b2 to keep an eye on the little ones