Do you mean they require playing session in interview now? In old time my girl just chatted with the principal, Ms Gile, in interview. That's all.
I think they may want to observe kids' interaction in a group during playing session . Please don't worry. Just make sure your child is happy and in good mood on the interview day.
In my own experience and feedback from friends, the school are very good at guiding children to love reading.
Never knew your girl used to be in Small World. You're definitely a very bright mom as back then SWKG wasn't even famous. You chose well! Did she move from SWKG to ESF primary at Year 1?