OK OK - first things first. I shouldn't have gone with the cheapest
guy in the local paper, and yes I should have checked out references,
and yes I should've got it in writing...yadda yadda...I'm looking for
advice on how to get my garden out this mess, not a lesson on how to
deal with local traders.

We had a crappy back lawn - looked the Himalayas, topsoil was full of
stones, clover everywhere, so we decided to take the plunge and get
the thing returfed. Aint a huge backyard - 4x10m - and the 6 quotes
came bcck ranging from £380 - £800 to do what we asked which was
pretty straightfoward.
1. Lift the current turf,
2. Get rid of the stones in the topsoil
3. Level off the ground with new topsoil
4. Lay new turf
Fairly straightfoward and yes, we went for the cheapest.

Bugger turned up when I wasn't there and scarified the old lawn before
sprinkling a token amount of "topsoil" over it(for "topsoil" read
"aggregate") and laid the new turf.
2 weeks later the turf itself looks OK (it is green and grassy), but
it is still lumpy and uneven.

Is there any hope for my back yard or should I just cut my losses and
start afresh?