Your 7.8 is likely because you didn't have any breakfast.
The liver pumps out glucose on a morning to give us energy to start the day. The liver switches off when we eat and the pancreas releases insulin to deal with the food. This is called first phase insulin release and it looks like this works well in your case because your meal time results seem to be lower than your pre meal readings. It may be that your second phase insulin release is slightly compromised (perhaps due to visceral fat) causing poor communication between the liver and pancreas as it doesn't appear to be keeping up with the liver output hence your slightly raised morning reading. It would be worth experimenting with an early light breakfast to see if that will give you a better pre-lunchtime result.
The first phase insulin, is insulin which is produced over time and stored and then when food hits the stomach it triggers the release of that insulin to deal with the food. The glucose trickled out by the liver in between meals and overnight is quite variable and needs communication between the liver and pancreas to get the balance right and looks to be what may be awry with your system rather than insulin resistance.
If you are reasonably fit and active then it might be just some visceral fat around your liver and pancreas reducing their efficiency and the Newcastle/Fast 800 low calorie diet might be a good approach for you to try to remove that visceral fat and restore proper function..... or I may be way off the mark!
Thanks so much @rebrascora for taking the time to explain all of this. It does definitely help me understand things better.
I tend to eat 2 meals a day rather than 3 and alternate between breakfast and lunch depending on what we have on the go that day. I will try and make sure I have something for breakfast from now on, even if it's something lighter. Hopefully that will help.
I definitely have too much visceral fat. I started 'cutting down' 4 weeks ago after my first HBA1C result but then found about about LCHF 3 weeks ago and have switched to that and lost 11lbs so far which I am delighted with (but have a very long way to go).
Thanks again for your post - it's hugely appreciated!
Mx