Prepping a cavity before screed

Hi guys

I have attached pic below. Customer has a window knocked into double doors leaving internal skin of brick and empty cavity, floor is asphalt on concrete which will be screeded with tilemaster trade flow dpm sandwich, how would you prep the cavity in order to bring it upto the asphalt level ready for screed?

Many thanks

 

Speak to tile master but possibly fill with there rapid repair mortar

 

Yeah they have a rapid repair that’s moisture tolerant. Just have to pack out the cavity with insulation. Or if it’s not deep enough take out a row of bricks. Dpm sheet and deep fill/rapid

 

Ardex a46