Thanks. Yes.
Given that this was not the first time I had experienced the issue with the duplicated recurring items I each time tried something different.
On the first occasion I created the recurring meeting using Outlook on my Mac. On the second occasion I used Outlook 2013 on my PC (Win 7). On the third and latest occasion I used the web interface to Outlook Web Access.
The other users are on Windows and the entries in their calendar are not duplicated. It is only mine that has duplicated and the two differences are 1) that I use a Mac with Outlook for Mac and 2) that I was the meeting originator.
When creating the meeting I had it recur weekly until a specific date later in the year. In case it is helpful, there are currently 4 duplicates on each date when viewed on my iPad or Outlook Web Access but five in my Outlook for Mac calendar.
Does this help?
Richard