BMM try and get it all in perspective.
Cholesterol is one risk factor for heart problems and other nasty circulatory diseases, but its effect is moderate compaired to other factors. Smoking of course is the major factor, blood pressure and family history are also a factors.
There are other links with diet and exercise, (although I have to say, the evidence is less robust.)
Look at why you want to lower your cholesterol levels. If you want to keep your doctor happy, a fasting test would usually give a lower reading.
If you want to work out your risk of developing heart disease over a certain period, then ask your GP to perform this calculation. (He will need to know your BP, Weight/height/family history, smoking status and cholesterol.)
If you want to just stay healthy, don't worry too much about the hype, cut down your total fat intake, avoid fats which are solid at room temperature (LARD!), eat lots of oily fish, (sardines are good), lots of fruit and veg, DON'T SMOKE, exercise for 20 minutes 3 times a week, get your blood pressure checked, and avoid PPRuNe medical forum, it causes too much stress !