I think the issue is not so much the verbage used around Jack and Clare's youth, but more that they're treated several times like children, particularly when Ellis and Clare have their late-night chat. That sort of builds an atmosphere. So I think in this case, because there's some stuff I can't cut (like the Cats remark), the solution actually is to take out the references to youth and children as much as possible, because it's already there in the subtext.