MDR-100ABN Replacement Headband Cushion?

[Sevoris]

Hi all,

I'm hoping that someone can help me with this issue. I've had my MDR-100s for ages now, still love them, and I'm keen to keep them as long as they keep going. But over the years the headband cushion has become separated from the frame and is in the process of collecting dirt. It's also quite aged, as the photo below will testify.

Is this something that can be ordered separately from the main frame of the headphones so I can replace it, and does Sony do that or is there a part number so I can look elsewhere?

Thanks! And, of course, photo of the cushion in question: