LUNs unknown group won't come online / rebuild Dell CX4-120

Hello,

I have a dell emc cx4-120

2 enclosures

Raid 6

I have disk failed replaced and Show rebuild 0%

I have found that if I put the failed disks back in they show as removed but rebuild 100%

I can replace the disks but disk 10 and get disks showing enabled and rebuilt but soon as connect disk 10 the rebuild changes to 0% and transioning and doesn't change

And I am unable to bring any of the Luns online

If I have the replacement disks in there are no errors just unknown Luns which cannot get online

If I have the old disk 10 in it reports failed disk and enclosure fault

The disks are emc disks same size as before 1tb

The Luns are set to auto own by sp but also tried manual

Rebuild tried adsp and high but doesn't rebuild with new disks in not even 1% in two days

I have downed all hosts and sp and enclosures and back on in order and good time between to no avail

Any ideas would be greatly appreciated

Thanks Danny