I found a workaround - I was researching driver signing and in the process found that this is "managed" at a low level by the "secure boot" function in your bios and after disabling "secure boot" and having Arma reinstall Battleye (by deleting the files from Program Files/Common) it now appears to run BattlEye without issues.

Before anyone asks - no I have not used any hacks or cheats, for this game or any other game. You'll just have to take my word for it.