Thanks the info.

Sounds like I might have left it too late this year, although a couple of
safari companies are still offering itineraries in June and July. I'm still
waiting for some replies.

One of them is saying July is the best time to visit East Africa, but it
sounds as though that might not be correct.

Bill, that website that tracks the migration looks very useful and I have
bookmarked it.

Regards

Michael