Insulation 
Underfloor heating
Underfloor heating pipes and DPM taped to blockwork ready for screed.
Screed was delayed due to a cement silo fault, but after waiting a few months due to Covid-19 another week didn’t make much difference.
This is a cement based screed delivered from a volumetric mixing lorry and pumped onto the floor. The leveling tripods are set level from my required 13mm down from the bi-fold door threshold; enough space for tile (9mm) and adhesive (3mm) and a spare 1mm for playing with!
The cement screed is more expensive but needs virtually no preparation for tiling. There is a little bit of foam that ends up at one end as the screed is leveled abd that can be scraped of with a paint scraper.
The last picture shows how level the floor and bi-folds are. The flowed floor level exactly matches the bi-fold threshold.