Our hats are off to Lucky Irishman Firearms for tackling this one for all the 805 Bren owners out there! Go Lucky Irish!
One thing to note is that (in our experience) the ACR stock likes to hit the brass deflector on the 805 receiver when it is folded (stock does not lock closed). Lucky Irishman might need to supply a new deflector, or users might need to modify/re-shape their plastic factory deflectors (only $4 from CZ-USA!). We still need to try shooting the rifle with the deflector removed, it should function alright, but does look a bit funky. The ACR stock is (in our experience) ergonomically perfect for the Bren+AR optics though... To the point where some shooters may not even bother folding it; even if the stock was fixed it would still be a great option. Again, hats off to Lucky Irish for making this happen!
I do not have any pictures of the stock/deflector interference, but here is how we had the stock mounted a while ago: