Hello, I’m about to porcelain tile a long established concrete floor with electrical underfloor heating and decoupling mat in about 1/3 of the area, then I’d like to tile the rest using adhesive underneath only. As there’ll be a 5mm+ height difference between these heated and non hested areas, what is the best way to level it all please? Self levelling under non heated areas to match height of decoupling mat? Thanks