I do not do eBay, so I have no advice for you there. Sorry.
I would contact PAG directly regarding accessories
https://www.paguk.com/catalog/45 (barndoors, diffusers, etc.)
https://www.paguk.com/catalog/48 (NiMH belt battery)
for the C6...
And no apologies needed (for being Dutch or anything else). We are all in it for the fun of video. While I certainly do not know nearly as much as many, I feel fortunate to know enough to help others...