As a type 1 diabetic on insulin you will have a restriction on your driving licence which says you test before driving and every 2 hours while driving, if less than 5 eat carbs, if less than 4 don't drive.
I believe that if you are pulled over and this restriction appears on a check of your licence you will be expected to prove you have complied with a finger stick test which will have a time and date recorded in your monitor. A libre scan isn't sufficient for DVLA.
We have the Libre for my daughter (she's eight so obviously doesn't have a driving license); we use it in conjunction with her finger pricker when she is doing strenuous activities or we want to have a picture of her blood sugar.
I can see the attraction of it.
Personally, I have a regimen which is for every 15 minutes driving, I have one mini jelly baby. As long as I am above 5.0 when I start driving, I am going to be fine with this, although I do try to run my sugars slightly higher before a long drive so I start around 7.0.