The Clark Building technically refers to just the older part of the building which contains the majority of languages classrooms, the library, the drama room, and a couple of offices.
This part of the Clark Building contains laughably small rooms, designed to house no more than twenty students whereas most classes now have over thirty. These rooms are not only small yet also now held together with what seems like a bit of tape and ancient blue-tac. All the chairs and desks in these rooms are different and contain little messages such as "I hate Spanish" "Yeah me too" "same here" on the bottom and a horrifying amount of chewing gum (this makes the lockdown drill much less pleasant).
The Copley Suite is the technical name of the modern, flashy maths classrooms that are surprisingly flimsy. It seems they made up for the lack of space in the languages buildings by extending the maths classrooms to a ridiculous length - in particular C116 where students cannot have covert conversations due to fear of having it echoed across the room. Furthermore, Mrs Chapman would likely benefit from investing in a megaphone.
Nobody really calls it the Copley Suite and just refers to the building as a whole as the maths block or Clark Building.