We had an extension built 18 months ago. The new floor is concrete with some sort of levelling on top which is perfectly level - poured by an specialist company the builder employed. The floor in the existing house is chipboard sheets. The builders did pour some levelling compound onto the existing floor in an effort to level it, they then laid laminate flooring for us (in a hurry because we needed it for last Xmas). There are some definite "low" points that can be felt when you walk on the laminate.
Today I had a carpet fitter in, and asked him if he could lift the laminate and solve the problem - but he reckoned it was more of a builders job than a floor fitters, and we needed to fix the underlying problem not just use leveling compound.
I know its difficult to guess, but would you think it was worth having another go at using a levelling compound? The builders implied at the time that if they used any more it would run into the next room, but I am thinking they just wanted to get on and get the laminate laid, and that it might be possible to target the low spots? Which are in the middle of the room not near the doorways.
It would be a big and very expensive job to lift the entire old kitchen floor and relay it - but maybe not so much to lift the laminate and "patch" the low points?