Hi
@Sussexmax, welcome to the forum. The increase in HbA1c is not helpful I am sure but you are still at the lower end of the pre-diabetic range so you are still doing well. In fact if you look at this from the other perspective, keeping your HbA1c so low over a period of years is actually an impressive feat.
The medication can help but like any thing that you take continuously, it may be that the medication is becoming less effective in your body. If that is the case, then changes to the medication or trying new approaches in other areas may help you to push back the increase. For example you could review your diet and lifestyle to see if there are any changes you could make there that might help. E.g. increasing exercise or adjusting the levels of carbs in the diet.
If not already proposed, I would ask for a chat with the Diabetes Nurse to discuss options and ideas. The fact that it is only 42 may mean that there are no concerns on their side as you are still not in the dangerous range, but if you ask to chat about it they may engage with you to discuss the options.