Damp Course Membrane Distance - Critical?

[The Famous Forry]

I have removed my old patio 60cm x 60cm concrete slabs which started from the back door of my house to the start of my garden, roughly 2.4 meters. The end of the patio is supported by a 2 course brick container wall running the length of the patio, about 4.4 meters. I have laid the hard core and compacted it. I have incorporated an elevation to guide the water away from house towards the garden. My elevation from my calculation should be about a 4cm drop at garden end but the top brick of my 2 brick retainer wall governs the elevation height making it only around 2.5cm drop. Once I lay the slabs I would be exactly 2 bricks below the DCM. To get bigger elevation, How detrimental to the job would it be if I was to end up about 1.6 bricks from the DCM Thus raising my hardcore level slightly on house wall. Any other remedies? Thanks regards David.