Thanks for the recalibration tip
BUT I found out that, while wanting to make a shortcut to reach it easily, I had inadvertantly moved the \color\ folders which normally lies under C:\windows\system32\spool\drivers\
What made me realise was Datacolor Spider 4 refusing to save calibrationas was suggested by KWDAVES (no directory)...
Replacing \color\ where it should be restored the display...
I'll need to re-calibrate