Replacement "Master" IDE Slimline Optical drive for Toshiba Laptop

Hi there,
I am looking for a replacement CD drive for a Toshiba Satellite Pro A120 (laptop). Been reading up on this for a while as every replacement IDE slimline drive I've tried doesn't work. From my research it requires a slimline IDE optical drive that is "jumpered" for master. As its slimline there are no jumpers so as far as I'm aware they are manufactured as either master or cable select. They can only be changed by flashing the BIOS or doing some soldering, or they can be bought like this. As I require a new one anyway I'd rather purchase one that was guaranteed to be compatible. Does anyone have any idea how to tell whether slimline IDE optical drivers come as master or cable select? Or somewhere to get replacement parts? I'm in England by the way.

Much thanks,
Dan Gent