Richard, I think that must be it - the upper registers are definitely a bit sharp to my ears. Maybe I possess perfect pitch but I rather doubt it, being a folkie (ducks to avoid missiles).

These digital pianos do supposedly utilise full range samples of real concert grands and uprights but as others have said that's not the whole story.

To be honest I bought one cos I couldn't face getting a real piano tuned every five minutes because of the central heating.

Never mind, when I win the lottery, I shall have my library, my music room and my Steinway....and a different coloured Citroen DS for each day of the week.....