Kitchen end panel or 18mm contiboard (Southcote RG30)

Hi does anyone have a kitchen end panel or piece of 18mm contiboard or similar 900mm by 500mm (or larger, I have a saw!) going spare before I go down to B&Q and buy a new one? Colour / condition doesn't matter as long as it is sound. It's to make a shelf for our car to go behind our daughter's wheelchair on the ramp so we can put luggage on it. Happy to collect from anywhere reasonably local (we are RG30 near Prospect Park). Thanks in advance!