agreed, chances are its an unbranded trade item, and you'll be hard pushed to find exactly the right one or part, probably easier to replace the whole unit... but post a pic anyway, as there is a wide base of experience and knowledge here, someone might recognise it, you have nothing to lose trying that. I had exactly the same problem with a kitchen tap that needed a new ceramic valve because the plastic lever snapped, i actually made a new one from a block of nylon, but thats not for everyone, too kme about 3-4 hours but saved me stripping the tap out and replacing it