After the advice I got in this thread I have bought Gluco Navii. It cost me under £30 for the machine and its accessories, 100 test strips and 100 lancets. I have only had it a few days but it has already given me a much better insight into how my body reacts to carbs. Much more for me to learn but I am finding the information this provides really useful.
I am also using an app/website called Nutracheck, which tracks calories and all the major nutrients including carbs. It's British made and recognises all the packaging barcodes I have shown it so far. It also knows about dishes in restaurants etc. It's a subscription ( a free week is available) but I find it really useful.
Thanks again for the initial advice I was given at the top of this thread. My glucose level was 8 when I first got up this morning but has been between 6 and 7 since 9:30, (chilli con carne and cauliflower rice for lunch) which I am taking as a modest win as it was 13.3 on my fasting test a couple of weeks ago.