I'm sorry if we all seem to be going on about this Clare, but if he is consistently getting levels that are off the scale of his meter (as indicated by the 'HI' reading) then he really should be getting much closer attention than a rushed 10 minute talk with a nurse and a 30 minute appointment a week later.
I would urge you to think about cutting right back on any carbohydrates in order to try and reduce his levels. Lean meats, eggs, vegetables (other than potatoes or sweet potato), cheese - all are preferable for now to bread, pasta, rice etc. - including cereal of any type, as practically all packaged cereal, however 'healthy' it may claim to be, is full of carbohydrate. Try doing a test when he wakes in the morning, and another test an hour after breakfast to see what sort of a difference there is in the numbers. I know the numbers probably don't mean much to you at the moment, but I think you can understand the scale of difference - a non-diabetic will be between about 4 and 6 mmol/l on waking.
I do not understand the delay in providing appropriate education and treatment, it seems far too unhurried given the indicators.