Its a long story, but I'll summarise:

New house with back garden turfed (and then returfed a few months back).
The garden slopes approx 1:10 towards the house and is north facing.
There was an old field drain leaking water at the back door which was
blocked up.
I dug a small trench across the garden at the back door and laid a drain
- covered with pea gravel.

However, the grass is still very squelchy for about 3 or 4 feet before
the drain - even in dry spells, it never seems to dry out.

The grass is now being affected and is not growing as thickly as the
rest of the lawn.

The soil is *very* heavy clay and seems to just sup up water like a
sponge and not let it drain down to the drain I dug.

Is there any hope of me recovering the situation? I have forked the
grass and put some sand down. If I keep doing this, will the sand work
its way into the clay over time and let it drain more freely?

Any advice appreciated.

g.