Fitting a lino flooring

[swampydrill]

I am having a new lino floor fitted on Friday around a new kitchen, there are 2 previous lino floorings down already which were fitted around the old kitchen. I am thinking of just removing the top lino and leaving the bottom as a form of underlay, only thing is that there will be some parts of the floor that aren't covered by the old lino and so would be a small dip, will this show up through the new lino or should i just remove everything back to the concrete floor.

 

[Cartboy52]

I'd rip it all up. It will probably show.
The stuff in our bathroom shows a slight step where one floorboard is a tad thinner than the rest.

The other thing you could do is if you are removing the top layer, is there enough there to lay on the bare patch, making the floor the same height throughout?