Triple Science gives you three separate GCSEs ie GCSE Biol, Chem and Physics.
And to add to that, Double Science leads to two GCSEs, Core Science and Additional Science, each being the product of testing knowledge in Biology, Chemistry and Physics. So the qualification is structured 'horizontally', so to speak, with a grade for each of two levels across all three subjects, rather than 'vertically' with a grade for each subject separately.
Although I think that in the past, when some students were put in for the Core Science papers in year 10 and the rest in year 11, it was possible to end up with 3 separate GCSEs, reflecting the same testing of the same knowledge as 'Biology', 'Chemistry' and 'Physics', but called 'Core Science', 'Additional Science' and (?)'Further Additional Science' instead.