You will most likely want to have only 3/4 subjects at A2. You will know which one(s) to drop (whichever you enjoyed less). Also make sure that the remaining subjects are useful for whichever course you want to do at uni.
Just saw you want to do engineering.
In this case you definitey want to keep Math, Further Math, and Physics for sure.
I reckon that chemistry is more useful than computer science for engineering but both are good.
You also didn't state if you are to do chemical engineering or not. If there is even the slightest of chances, YOU NEED chemistry, even for A2! (chemistry really will helps and may as well be required).
If you do chemical engineering, you should check relevant unis if there is a possibility of needing math, FM, physics, and chem (yes all 4 at A2, which is recommened).
My recommendation for all cases: math, FM, physics, chem (all at A2). This is due to the fact that math, FM, and physics is LESS work than 3 very different A levels so chemistry shows you can handle a demanding workload.