Skier wrote:

I am currently in the process of doing the garden which is a sloping
surface(towards the house) at the moment.

I am going to be leveling and building a wall to make 2 level surfaces. At
the moment the ground is clay and water does not drain through. Obviously I
have to include some kind of drainage into the design. My initial thoughts
were to create some kind of french drains angled toward the house so that
the water ends up where it ends up at the moment. I have had a quick look at
what is there and it looks like a load of gravel near the foundation and if
I dump water into it then it dissapears after a few seconds. Does anyone
know if it is regulation (house was built about 4 years ago) to include some
drainage around the house. If that is the case I think I will be ok doing
what this. any thoughts?

The other option I have is the rainwater downpipes ar in the same location.
Can I "T" into this and connect my land drain? Though about a sediment trap
before the T.

Your best option is a manhole into the surface water drain. It is very
silly to have loose water slopping around a house and especially
dangerous in clay soil where it might lift and drop the foundation
seasonally.

You can get some pastic ring inspection worreverey-callems that fit on
onto the other. You might want to brick up around them if you are going
deep but they are OK for 3 or 4 layers:
http://www.pavingexpert.com/drain05.htm

If you make a brick manhole then you can make it large enough to have a
weir to collect debris in one chamber and drain out the other. That
might be cheaper than the road drain thingie you seem to be discussing
elswhere on this thread.