In a nutshell... No!
You can trade in anything Hi Fi related, even if it is damaged, marked, not working. If your old item is still working and you just want to look for an upgrade, or something a little different, thats also absolutely fine. The scrappage scheme is a great way to try add a new component, upgrade or just try something a little different.
Of course we are always on hand to help with advice on upgrades, new products or any other queries you may have!