While I agree that it could be calendula, it could also be a highly invasive plant called hound's tongue. It, too, has sticky, resinous leaves, and a very similar shape, especially in rosette stage. I'd keep an eye on that lil bugger if I were you, Jules... Hopefully, it is calendula- hound's tongue can be quiet a bear to eradicate.
Those are the largest trousers in the world! Especially when next to this ad: