Odd one.... I lost write access to my pool so fired up the Drive Pool GUI and had a single screen asking to "Transfer Licence to this PC" which I did, and then my pool was all good. No idea what caused Drive Pool to think I had a new PC / HW though I had been playing with some OC settings and had a Win 10 BSOD / repair check as a result, but that is the only thing I could think of. Running 2.2.0.682 Beta
Thanks
Nathan