That's because everyone on this forum is singing from a different song sheet to the one used by our GPs. We can't blame them, their hands are tied. It's called NICE, National Institute for Health and Care Excellence.
https://www.nice.org.uk/guidance/ng28/chapter/1-Recommendations#blood-glucose-management-2
I haven't checked the numbers exactly but I think this document will explain why further action wasn't taken. It's section 1.6.5 Targets. The numbers you quote may not be exactly within the ranges specified but sometimes I think there's an element of allowing for inaccuracies and they might not worry about the odd mmol/mol here or there.
Doctors use the HbA1c as the gold standard, despite it's inaccuracies. I usually have one annually, not 6 months or a year because they know I monitor continuously. I did go through a patch of complacency and got a shock last christmas but while I monitor continuously I don't have to worry too much about the HbA1c and certainly wouldn't rely on it as the only way of measuring my BG. Surely your personal BG monitoring must have warned or indicated an HbA1c that you wouldn't like.
So really between May 2016 and April this year your regular BG monitoring would have shown some issues. A good reason why monitoring is necessary.
1.6.9 looks very interesting.