Hi Phil,
Your profile doesn't say whether you use a rapid-acting as well as the Lantus. If you don't, it might help to add one to get your BG down after food so that you can reduce the Lantus dose - that might help to avoid the massive highs follwoed by the hypos once the Lantus kicks in. Rapid-acting is much easier to see what's going on as it is taken with food and leaves the body within 5 hours, so you sort of know where you stand.
Sometimes, a particular insulin just doesn't suit someone. Maybe lantus doesn't suit you and a change to Levemir might do the trick - although you would probably have to split the dose morning and evening to cover the entire day.
Smidge