I've got a set of six that I had re-lined with a wet or dry friction material as I couldn't get hold of any for my race bike.
After being dubious, I used them once at Snetterton and they performed very well.
They cost me around £140. Still got the bill if you need to see it!
I've changed to an RS type set-up for the gearbox and clutch now, so I'll sell these plates for £120 plus postage, or we could meet up half way as I live in Stockport.
As far as I know, these parts have long been unobtainable.
PM me if you're interested.
Cheers,
Roy.