Studying in Germany as an international student urgent help! From the UK

So I really need some advice/help on how to study at a university in Germany. I'm from the UK and have completed my a levels, however they are not equivalent to the arbitur because I don't have Maths. I was under the impression I could study at a 'Studienkolleg' for a year to make up for this, but I am not eligible as I have previously done my a levels.

The majority of countries in Europe have a university entrance qualification e.g. A levels , that are equivalent to the German arbitur. However, if you don't take certain subjects e.g. Maths, you will not meet the requirements for admission at a German university. I'm wondering if anyone has had any similar experiences and if there's a way to gain the missing qualifications in Germany somehow?

Any advice would be greatly appreciated :)