Thanks Eric - so if you can't reproduce the behaviour it would suggest that the problem is not in the Logic project, but is a fault somewhere else in the system. I have disabled the audio interface, but the problem persists. I trashed the preferences, opened Logic, enabled advanced tools and created 5 tracks, each with a region, but without a plug-in. I noticed that nearly always whatever note I select, the tooltip displays the information for the first note in last track in the score. If I rearrange the tracks in the main pane then the tooltip information changes to reflect the information of the first note for the track which is now at the bottom.
I added a new track at the bottom, with an empty region. Now the behaviour is really weird, with very large bar numbers (279611 2 1 64) sometimes indicated as a negative number. If I hold the note for a few seconds the display sometimes changes to something more believable - such as -3 1 1 1, but still incorrect. A lot of the notes on the different staves have the same position information (279611 2 1 64) but some do not.
I have just solved it! A few weeks ago I installed an app called Moom - which is a great little app for automatically resizing windows - I do recommend it. But, I have closed it down and now everything is working as expected. Thanks for your help!
Also check out this:
Have a great day!