Thanks for the feedback I think I might give this a miss as it sounds like I could be chasing unreliable adapters, can you recommend another Buffalo 4 bay SATA unit.
Dair enough. I do not have any of the more recent Buffalo devices (all of which are SATA based), so cannot make any sort of recommendation based on experience.
If I was looking for a NAS now I would probably go with an UnRaid based device so that I had the flexibility of adding more drives (potentially of different sizes) as my requirements grew, or swapping out individual drives for larger one without the need to change all at once while still having all the advantages of RAID. Whether a device like that would make sense for you depends on what functionality you want (if any) over and above basic network file storage.