As I was told, car batteries are 'assembled' by most companies who have their names on them. The plastic box, acid, and plates are bought from separate suppliers, hence two companies such as Halfords and Varta seeming to make exactly the same size and shape battery. The cost of these components are what prices the final product. I have a Halfords battery and it is fine. As these will almost definitely be made by somebody else and just brand labelled (I don't expect Halfords have a Battery manufacturing plant) then the make is pretty irrelavent as the components for the battery all come from the same original suppliers regardless!