HELP !!!

All of my spanking new camping stuff has now arrived, including a campingaz bistro burner, but I've a problem tracking down butane gas cartridges size CP250 or anything compatible. I thought I would get them locally, but ALL argos stores (10 nearest) are out of stock (summer festival season)and Milletts in Eltham have closed down - is that camping supply shop near Knockholt still trading? Anybody got any pointers?