Well, I think the final result here is that they are not interested. They deleted the message sent to support without even replying and there has been no communication whatsoever. That's a shame because, while I readily admit that they are in no way obliged to offer a discount, the lack of any form of communication - even if it was a simple "sorry, we don't offer discounts" is troubling.
That then makes me wonder about what would happen if I purchased their product and there was an issue. If this is my experience from my first attempt to communicate with them then it doesn't bode well. Mark, maybe they were better with you because they could see that you have a wealth of YouTube content and a platform more people listen to ?
I'll now rethink this one. Thanks again Mark for your attempt to help with this, much appreciated. Thanks to everyone else who commented.