Best of luck Lee, they're like rocking horse droppings, although easier to find than the front mats...

My orange '70 had the rear mat but nothing in the front so i bought one off a forum. It was only when i fitted it i realised it was a different texture, so worth posting a picture of the front mat so we can see what you've got. Should be square bobbles for up to '71?
In my case i ended up buying a correct mat at dubfreeze and sold my wrong one for more, so worth buying any one that you get offered.