I had to change a piece of boot trim last year - in the end I sourced it from a new 850 breaker being listed on ebay. No parts were being listed, it was just an advert saying that the car was being broken and all parts were available. I dropped him a message and we agreed a price - I suspect that is your best option too, as these parts as getting scarce nowadays.
Bear in mind that a phase 1 V70 and 850 estate share most boot area parts
Good luck!