how soon can I use self levelling on new floor screed
 

my first attempt at laying a floor screed on top of the concrete
oversite yesterday, in total 40 x 25kg bags of sharp sand mixed and
laid on my own- I'm knackered!

the depth I had to make up due to previous builder 'mis-calculating'
was 135mm. I laid some spare 50mm kingspan then 85mm of screed on top.
as I was doing it on my own, and my 1st time I didn't managed to get a
really flat surface

although the floor is generally level, and even though I'm going to be
putting quarry tiles on it, I'd like to level the floor up first.

so, question, how soon can I lay some floor levelling on it? the type
of stuff B&Q sell

cheers