Hope you can see these? first pic was of house before flooring was laid if you can see join which as at the right hand side it runs the whole length of room 20ft, The 2nd pic is of line appearing through tiles and 3rd is after they had repaired cracked screed with a epoxy resin but line showing through again. They are now saying they cannot do anything until we get structural engineer to confirm subfloor has stopped moving. Can you see join beforehand? Should they have laid over this?