If you want spare parts for Harman/Kardon audio equipment in the UK, don’t ring the number on their website unless you speak German. Even if you do speak German, all that will happen is that the nice lady in Austria will eventually give out a phone number for people who might be able to help. Speaking as a Germanist, I believe the UK and indeed the world would be better if more of us spoke German, but I do think this is a lot to ask of their median customer, especially as even those of us who do speak German might struggle to translate whatever recondite subwoofer doodah we’re after.
In order to spare anyone concerned the unscheduled German oral exam, that phone number is +44 1728 746 500, and if you ring it someone in Saxmundham will answer in English.