I can only give my personal view on this. When I was accepted as a patient rep on the Guideline Development Group one of my biggest hopes was that there would be a weight of evidence that showed how effective CGM was and that the guideline would widen the take-up of CGM for all the reasons you are all stating.
I had never had experience of any kind of continuous data at the time but on forums and blogs I saw time and time again how much difference it seemed to make to individuals.
Unfortunately the reviewed evidence just did not back that up.
The thing is that CGM is SO expensive that you actually have to have pretty hefty effect sizes and you have to see these pretty much all the time for the cost of the treatment to balance the long term risk of complications. Sadly the reviewed evidence (and I absolutely trust that the brilliant technical team searched for and found everything that could be included) showed a significantly mixed bag - with no real explanation. In HbA1c terms sometimes it dropped a smidge (.3% on average), sometimes it was not affected at all. Generally people felt better with CGM and on balance there were significant (though again not universal) improvements in hypoglycaemia and severe hypoglycaemia - but really nothing much to cling on to for HbA1c.
Now my guess would be that most of these studies are funded by the machine manufacturers - so presumably they show the devices in the best light they can - and even so they weren't able to show really big numbers consistently.
It's like it works brilliantly for some people, and not at all for others - and actually not very well in trial populations (which is weird because often these are just the motivated types you'd expect it to work for).
Undeterred the GDG commissioned an entirely new economic model (section 8.2.5) which ran through a large computer-generated population designed to reflect the average T1 in the UK and with the average incidence of complications at their averaged HbA1c. Then they ran 'lifetime' CGM cost from average age against average benefits (including A1c and 'quality of life' measures) to see whether the numbers stacked up.
They didn't.
So they added best improvements and most intensive BG strip usage into the mix so that effectively everything was weighted toward CGM winning. And it still would not measure up.
10x a day = £1000/year
CGM = £3,500/year
But you just don't seem to get £2,500's worth of benefit each year in NHS terms - unless you are actually struggling.
With the (pre Libre) evidence that was considered - it seems that on average CGM is just too expensive and not effective enough for 'general release'. I'm gutted about it, but I have to concede the cold hard economics of it.
Yes it might get a motivated patient from 7.0% to 6.5% or 6.0%, but the 'curve of complications' is really starting to bottom out down there and the incidence of complications is lower... so fewer savings to be made... Unless of course you are in and out of A&E with severe hypos multiple times a year. etc etc.
I am not sure whether the Group will revisit CGM in the light of Libre (does seem likely) but I will have to opt out of any further discussions on CGM because I accepted a free trial of the Libre and so, in NICE terms, I have a conflict of interest.
In terms of the guidance and driving - I think it's important to recognise that CGM and DVLA rules are not mutually exclusive in that carefully written recommendation. If you are having lots of severe hypos then clearly the DVLA are going to be a bit twitchy (and rightly so) but this is an 'any' list not an 'all' list. The last two bullet points
*frequent (more than 2 episodes a week) asymptomatic hypoglycaemia that is causing problems with daily activities
*extreme fear of hypoglycaemia.
Could apply to many T1s who would benefit from CGM and are not necessarily be banned from driving. It's down to the clinic/consultant to make a clinical judgement. Heck depending on whether whoever it is thinks 3.9 counts as hypo I certainly qualify under the first one if I argued strongly that the fear of those levels without warning signs *every time* was ruining my quality of life and causing me problems.