Our contractors effectively treated the EPS slab as if it was level ground (i.e. they ignored it) and built their traditional steel lattice & formwork / shuttering on top. Slab and a 100mm kicker first and then built off this as they did the walls in sections. The kicker is necessary to hold the vertical formwork straight on the slab. Water bar on every join (inspected by the Sika rep) and Sika additive in the concrete as this was our sole waterproofing method. I don't think any serious con