Quadfather
Headphoneus Supremus
I think as it is a discontinued item, parts will probably not be available.
Maybe if you bought the Diana edition, you could ask the question to TEOS info@theevolutionofsound.com , though they are not selling them anymore, they may have a more reliable contact at lotoo who can at least give you a yes or no.
The new US distributor is checking into it. I would think any Lotoo Paw Gold back panel would screw in and look fine. The blemish is barely noticeable, but I am a little crazy about keeping my stuff in perfect shape