karmahappytoes said:Location first. City or County? Whom allow this to pass inspection? Read your contract!
Because of OP's use of the expression 'sleepers' for timber-lined or 'raised' beds here in The States, I suspect OP is in the UK. I frequent a UK garden forum regularly and hear this word usage a lot on that forum. That may even complicate the drainage problem seen in th photos even more, as so much of the UK they say has a lot of clay in the soil. Of course, the amount varies from region to region. Also their real estate laws/guidelines are quite different from ours. Correction jobs this big must go through their local Council and get approvel. Perhaps a UK member here will step in and offer some suggestions that will meet landscape addition/change requirements where OP lives.
