Garden drainage

[Pete83]

Hi
I’m hoping for some advice on drainage around my house. I’ve dug out plants and down 150mm as the lawn was level with the damp proof course with a view to lay turf and then gravel in the trench. There’s no actual signs of damp in the house but it’s on a slope and wondered if I need to install a perforated pipe and connect to the downpipe or if pea shingle/ decorative stones is enough on their own.
Many thanks

 

[^woody^]

All rain water will drain through the grass and dirt, so you don't really need a drainage trench or drainage to move it away as it wont be doing much.