Hi Noris (and all who responded!!) I worked out the problem. Looks like when I copied the files over from my NAS drive they got corrupted some how. I could play the songs directly from the NAS drive using Foorbar2000 but when I tried to play them from the internal storage on the NUC foorbar2000 said the files were not a playable format. So I deleted them off the NUC and re-copied them from the NAS forced a re-scan and SUCCESS!!!
FYI Noris - the one file I sent you to test was from the NAS drive not the NUC.
Thank you all very much for your help and suggestions. I couldn’t be more pleased with the fantastic product ROON is, the help from the general ROON community and the excellent customer support from the ROON team.