Thank you so much for your reply. I hadn't realised that the metadata was removed due to privacy concerned. That makes sense with so many of us sharing photos.
Maybe I should have given more background information as it might help -
I have an old iPad (iOS 9.3.6) and it has photos on which aren't on iCloud. I want to move these photos to iCloud so I don't lose them. If I try to turn on iCloud photo library it says "Photos synced from iTunes will be removed - Syncing photos via iTunes is not supported when iCloud Photo Library is turned on. 4,402 photos will be removed."
So I thought I could set up a shared album and put them in there, share it with my Mac and then then using my Mac, copy them into my Photo library which is on iCloud.
When I tried with a small number to test, I can see the correct metadata when viewing the photos on the shared album on my Mac but as soon as I try and copy, or export/import the date changes to todays date.
Hopefully that makes more sense.
Thanks again Léonie