Thanks for your reply JB :)
It will be running freebsd. Have updated the bios to the latest version via a windows install. Have tried ubuntu (kubuntu), debian (kali), windows10 and freebsd(12.1) on it, but it doesn't recognize the drives at all from bios right through. If I have it plugged into the x16 pcie slot, the pc wont even boot. I'm assuming it's a bios setting that I'm missing. Have tried quite a few settings and been at it for days trying to work it out. The x4 slot is pcieV2 and the adapter is v3 with the 2280 m.2 in it. The x16 is V3. Is there a bios setting I'm missing or is it just not going to work?