Order should of been
Screed goes down
Leave 30 days
Switch on UFH low temp to force dry the screed for 30 days
Moisture test
If dry smoothing compound , 2 days later lay LVT
If still got damp in it switch heating back on
Waste of money so don’t buy it.
You won’t have any sign of damp as a carpet been above it so it’s been breathing.
Is the floor black or clean concrete.
Are the skirting on ?
Imo it needs a Dpm at that age property if it’s a ground floor.