Hi Deegee, just shows you, us 'old hands' can still learn a thing or two!
Although when I was diagnosed we had 'Exchanges' consisting of 10g carbs ever since the newer insulins came out it's all been based on guesswork and some people are better at that than I ever was. So this 'new' round of carb-counting training was brilliant for me - I now have 'rules' to calculate my doses and corrections, rules to check whether my basal insulin is doing what it needs to, exactly when it needs to do it - and what to adjust if it isn't. Fantastic.
If you haven't been offered an actual formal course, there is an online one, so shout up if you want to have a go at that.