For the carpets inc the fabric door cards and ceiling use a foamy fabric cleaner and follow the instructions. You might find fabrics are damaged though if it is excessive dirt.
as for plastics it's just a case of soapy water and elbow grease.
If you want to get some proper products have a look around the cleaning secion in Halfords.
But i'd just do what I said above over and over until it is clean!
