Linear drainage channel (Springfield CM1)

Hi, I know it's a long shot but we are looking to build a step next to the house and so need a piece of linear drainage channel to put between them to protect our damp proofing. If anyone has any left over from a building project or from something you have taken out, we would be very grateful. I can collect from Chjelmsford and surrounding area. Alternatively, if you have a spare piece of damp proof membrane that we could use instead, that would also be great. Thanks for reading.