If you want to go to a decent uni:
(If you’re choosing further maths)
Maths, FM, (another subject-business studies/economics/product design)
(No further maths)
Maths, Economics, Product Design
Top uni:
Maths, Further Maths, Economics (fourth subject; product design or finance
That’s pretty much it, don’t make the mistake I made. Use the options above to guide you