@trevorflowers not sure where your based but you could try 2 1200x 600 cutting mats if you cant get a 1200 x 1200 at reasonable price.
or if you dont need the green and markings, search for "Heavy-Duty Workbench Cutting Mats" they are generally clear or translucent thick material that self heal and protect your bench / desk, oh and will be a lot cheaper than the same sized green looking cutting mat as they get pricey at the larger sizes.