Well that's another couple of hours searching and nothing, starting to think it's bugged as every now and then I go to a yellow blip and there is absolutely nothing there.
I'm now using the disttocore mod (so I know i'm in the right range), I've got Legendary object detector, Exotic scanner and Exotic radars and still only find wrecks, beacons asteroids no more science labs, getting frustrating now.
I've found about 6 sectors with the rings of asteroids with a big one in middle - that's the portal bit obce you have 8 artifacts isn't it ?