I received a call today from the Samsung authorised UK repair centre. The affected soundbars require a 'new part' (motherboard) and due to the number of failures Samsung is out of stock of said part.
He told me that they (Mint Group FX) have ordered the part and if they are unable to get it by next Wednesday 25th March, then I will either receive a refund or replacement unit.
So that will be a minimum of 14 days waiting and listening through the dire TV speakers! 1st World problem I know, but frustrating non the less.