great idea but 85% is not tolerable for medical reasons it would have to be 99.9 or better reliable for DVLA and driving lisencing purposes this is why Libre is not accepted by DVLA yet.
Diabetics on insulin have to check there blood glucose levels at least 2 hours before driving which is mandatory.
I would love there to be a better way and in the future there will be. its a start for us. keep up the research and well get there.