Think your consultant expects too much...........zero hypo's..........really
Hypo's are impossible to avoid completely and the usual cause is mis-calculating a meal-time bolus and exercise, if you go below 4 occasionally but not below 3.5 then that seems quite normal to me.
I can go 2-3 weeks without a hypo then have a a couple within the space of a day or two, but personally I wouldn't want to be in the 3's everyday and try and keep my bg levels above 4.5mmol/l all of the time (well whenever possible), ideally I like to be above 5 but below 6.5 pre-prandial and below 8.5mmol/l postprandial.
Fortunately I've never had assistance with a hypo in 34 years and I think that's because I don't aim for tight control, still have very good hypo awareness symptoms.