Thank you all for your quick responses and guidance.
It is much appreciated.
I has occured to me that perhaps these discs had been previously used and so there would be problems with additional licences.
I am surprised that the Company Symantec and Amazon allow such a possibility. I had imagined buying a disc from Symantec would not allow such third party use of licences. If indeed is what is happening here.
Because of the possible doubts and the fact the retailer has not responded, I will not be puchasing from them.
Thank you also for the suggestion to download the software direct from Symantec site and use the purchased key. I had not thought of that safer approach.
Best regards
Castilonia.