My son has very much the same problem as 'billroberts' inasmuch his soil is heavy clay and there is also a slope to his house rear wall from the rear garden. Before he moved there someone had built a patio but had brought the level up to and sometimes over the damp proof course so that is coming out and dropped to the correct level (6"?).
I am all for doing what the DIY Doctor suggests i.e. creating a fish pond or a sump of some sort but using a sibmersible pump to force the water to the front of the house to a surface drain. There is no way around the house so those would have to go over the garage, down to the ground where the slope is away from the property. Would a concrete sump suffice if the interior was kept free of particles?
Do I make sense Mr DIY Doctor, and would it be legal?