In other words: Just wait for the data transfer to be complete.
I raised my query well after the data transfer had completed. If you read my original note it was already more than 24 hours after my initial installation when I raised the question.
I found a solution though, as no automatic update did take place. It turned out to be simple and obvious after all of that.
When you right click your games in the library and select 'properties' from the context menu, once the Properties dialogue box has drawn itself, you then select the 'Local Files' tab and then click the 'Verify Integrity of Game Cache' button and after a little bit of a wait the application detects errors and downloads fixes including the missing update I asked about.
I probably should have posted this observation earlier.
Thanks for everyone's notes though.