Hi scottishkate,
That's a bit of a bummer! :evil: Sometimes there is no justice, eh?
It does have the sound of the dawn phenomenon, where your liver de-activates some of your background insulin first thing in the morning. It was quite a big jump too, 4.5mmol/l in 1 hour.
It suggests, particularly as you say it happens often, that you have insufficient background insulin.
I'd be reluctant to suggest simply taking a bigger basal dose before bed, because of the attendant risks of overnight hypo.
One possible solution would be to split your basal dose in two. The bedtime dose will keep your bs steady overnight, then the balance in the morning might help offset the dawn phenomenon.
I think your bs kept rising because some of the insulin you used to cover your breakfast was swallowed up by your higher bs, leaving less to deal with your meal, therefore another rise in bs. A 'correction dose' is sometimes necessary to offset this rise so that your 4 units can concentrate on your breakfast!
I hope that helps. All the best,
fergus