I had mine for cancer last year so again a slightly different way of getting here from some of the others. As you've probably already realised you need to be your own advocate as I'm not sure you can rely on the NHS to always get it right. I've learnt the hard way the impact of having my treatment spread across 3 health boards and that's before I even get to the diabetes support which has been pretty much non-existent since I left hospital.
Things I've learnt...you need to carb count but not all carbs are equal. I left hospital with firm instructions to take 8 units of rapid insulin 20 minutes before every meal...queue a couple of months of rollercoaster highs and lows. The CGM is a guide and helps with trends rather than absolutes. And with no glucagon things like the 'dawn phenomenon' shouldn't happen but they very much can. Many health care workers won't be familiar with type 3c or will tell you its just like type 1 but as Roland explains there are significant differences.
Trying not to paint a bleak picture but it will be challenging. On the plus you can eat pretty much what you want once you get the insulin right. Today I had bacon sandwich for breakfast, fish and chips for lunch, pasta for tea and something called caramilk chocolate which I think is Cadbury's version of the Caramac bar for viewers of a certain age.