[snip]
I'd agree with the watering. The turves have very shallow roots until they
bed in. When my brother-in-law laid his lawn, he was advised to water for
about an hour each night - it takes a shocking amount of water! He kept
this up for a very long time and his lawn has taken nicely.

FYI, as a general rule I've always heard that if you need to water, water
long. The water needs to have time to penetrate down to encourage rooting
otherwise only the top inch or so of soil gets wet and the roots stay high
up. As soon as you stop watering, the roots are too shallow to find their
own moisture!

Paul DS.