My current ldl level is around 2.3 mmol/l. i have a few minor plaques that are not of significant danger. i am wondering if i need to increase my current crestor level from 5mg to 10mg?

Your LDL is close to the upper limit of normal despite a statin. While it may be necessary to lower the LDL further because of the presence of vascular disease, it is important to undertake other preventive measures such as exercise, a good diet etc. A "few minor plaques" does not provide much information unless their location and other details are known. Get your doctors advice, please.