Old floor + newfloor HELP!

[nyck]

I've had the kitchen extended and the the new floor screeded last night.I was advised to lay a Latex over it in a couple of days or leave a few weeks to dry then PVA and latex
The problem i've got the old kitchen floor has got loads of tile tile Adhisive stuck down and is a Pig to remove .So i thought i'll latex over the top over the Adhisive but i've just noticed the old floor theres a 15mm slope over 2.4 metres and the latex can only be layed 6mm thick
The slope is not a problem its getting the old floor flat/smooth so it can be tiled or laminated ,if i use latex over the old tile adhisve or even if i remove the adhisive will i just run down the slope

any ideas
Pictures below

thanks nick

 

[mattysupra]

subfloor needs to be flat and smooth, not level.