Please don't panic Pip. It may not be down to what you have eaten. It can be genetic, and you don't yet know what your breakdown is.
I can only speak from my own experience, but on diagnosis my cholesterol was high (January) and since then I have been in long debates with my GP over statins. I am not taking them, with her agreement. (purely my personal choice). Since cutting right down on carbs and increasing my dairy fats my cholesterol has improved a lot. My component parts are all normal and my ratios and triglycerides are excellent. This has been entirely down to an extra walk a day and diet. Nothing else. I don't have very high fat, but I do not eat any of the awful plastic low fat substitutes. I eat good fats - butter, cheese, full fat yogurt, mayonnaise, cook mushrooms in butter, use rapeseed oil for frying (olive oil is similar), and loads of oily fish.(salmon in my case).