An update for you of sorts... (nearly a month later!!!)
They posted out the replacement set very quickly but unfortunately some numpty at HK UK sent it out using an international Parcel Force service, so instead of being delivered domestically it ended up going to Jersey which really confused the bods at Parcel Force!
Safe to say after me doing HK's tracking work for them and calling up Parcel Force Customer Service, HK admitted making a mistake and have offered to refund me for the faulty gear either in bonus points (no thanks!) or through my original payment method: PayPal, which is what I've opted for as I've bought a combo off someone on the forums in the meantime!