Recommendation needed for work to level section of garden, removing low wall and concrete

We're putting a shed in at the back of our garden and need someone to level the ground out.  This will involve demolishing a low wall which is three bricks high (probably a couple more layers of brick as foundations too) and a section of concrete which is not in good condition.  Getting someone who could remove the rubble too would be ideal.  We're in N15 - South Tottenham area.  Very grateful for any recommendations based on recent experience.