Leveling the garden before laying turf

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The garden was dug up. The person engaged by me insists just a manual rake can create a level surface on which they will lay turf grass. I am worried that will leave a wavy garden and just an eye inspection cannot catch the troughs and crests. Is there a more reliable way to have a reasonably level surface. Not expecting lord's or Wimbledon. 

Does a light roller help? 

Loxley

Using a roller to level it will crush down the high spots, making them compacted, and leave the low spots uncompacted. Alternated treading and raking, using a long board to level, is probably better for the soil.

KT53

Once dug over the area needs to be levelled, this can be done by eye, but then 'heeled' all over ie walk with little steps all over it with weight on the heels.  That will firm the ground and identify any high or low areas.  Rake over again to correct the defects and it should than be ready for turfing.

As indicated by Loxley, a roller may reduce the high spots but will do nothing to correct the dips.

The underlying problem is that any problems with a lawn which hasn't been properly prepared aren't generally immediately obvious, and you can't walk on it for a few weeks to discover unevenness.