@BaconAndAvocado My DC is doing computer science at a top ranking university.
Maths and further maths are a must for CS. Even though they cannot ask for further maths as not all sixth forms offer it, the vast majority of those applying will have further maths. For A levels you have to love it as it will usually make up 50% of your timetable. It is usually a 4th A level as in its own right it isn't a full A level if you are also doing maths. DC would also recommend taking CS at A level. He did it for both GCSE and A level. This means part of your first year degree is easier as you already have the basic knowledge down.
I think this thread on student room sums up the not so different courses of CS and Software Engineering. DC is a coder but still chose CS as felt it had wider application in the real world.
www.thestudentroom.co.uk/showthread.php?t=4833248
Plus this is the listing for top ranking unis for computer science
www.thecompleteuniversityguide.co.uk/league-tables/rankings/computer-science
And a bit of general advice, entry grades are just that, the lowest they will take applicants in on. That means if they are asking A⃰ AA the vast majority of them will have 3 x A⃰ at least, then 2 x A⃰ . This is for oversubscribed universities who can pick and choose who they take. The higher grades they get at GCSE the better they will do at A level. Maths in particular is one where a 7 at GCSE will probably see you with a C at A level because they are missing large chunks of baseline knowledge to build on. They can get higher but it requires a some serious effort on the child's behalf.
If you haven't already looked, research how much maintenance loan your child will get based on household income and then look at accommodation costs. I think Warwick Uni showcases accommodation costs really well, easy to see cost from low to high. Just so you know the financial side of things. Some uni accommodation is cheaper whereas others can be very expensive.
warwick.ac.uk/services/accommodation/studentaccommodation/undergraduate/ugresidences
And good luck to your year 11. Almost makes me nostalgic, but not quite 