'Take a decision' is correct in British English. It is less common than 'make a decision', but it is still widely used. It tends to be used for more formal and weighty decisions. For example, Prime Minister Tony Blair TOOK THE DECISION to enter the Iraq war in 2003. This sounds perfectly normal to anybody who is familiar with British English.

I agree with Su.Ki; "take the decision" is fine, and it is not that rare in UK English: https://books.google.com/ngrams/graph?content=take_INF+the+decision%2Cmake_INF+the+decision&year_start=1800&year_end=2016&corpus=18&smoothing=3&share=&direct_url=t3%3B%2Ctake_INF%20the%20decision%3B%2Cc0%3B%2Cs0%3B%3Btook%20the%20decision%3B%2Cc0%3B%3Btake%20the%20decision%3B%2Cc0%3B%3Btaken%20the%20decision%3B%2Cc0%3B%3Btaking%20the%20decision%3B%2Cc0%3B%3Btakes%20the%20decision%3B%2Cc0%3B.t3%3B%2Cmake_INF%20the%20decision%3B%2Cc0%3B%2Cs0%3B%3Bmake%20the%20decision%3B%2Cc0%3B%3Bmade%20the%20decision%3B%2Cc0%3B%3Bmaking%20the%20decision%3B%2Cc0%3B%3Bmakes%20the%20decision%3B%2Cc0#t3%3B%2Ctake_INF%20the%20decision%3B%2Cc0%3B%2Cs0%3B%3Btook%20the%20decision%3B%2Cc0%3B%3Btake%20the%20decision%3B%2Cc1%3B%3Btaken%20the%20decision%3B%2Cc0%3B%3Btaking%20the%20decision%3B%2Cc0%3B%3Btakes%20the%20decision%3B%2Cc0%3B.t3%3B%2Cmake_INF%20the%20decision%3B%2Cc0%3B%2Cs0%3B%3Bmake%20the%20decision%3B%2Cc1%3B%3Bmade%20the%20decision%3B%2Cc0%3B%3Bmaking%20the%20decision%3B%2Cc0%3B%3Bmakes%20the%20decision%3B%2Cc0 If you switch that ngram to US English, you will see that "take", while not unknown, is indeed rare.

I don't think I have ever heard anyone say "take a decision." Are you sure you heard/read correctly? If you did indeed hear correctly, please show us how it is written in the context you found it. I have only ever said "make a decision" and it means to follow a specific agreed upon course of action. For example: "Despite what they wanted, they made the decision to stay home." "We have to make a decision on the new budget this year." "I hope you've made a good decision regarding your future." I hope this helps. If you have any more questions, please let me know.

The only way I could imagine "take a decision" is if you are taking the decision making process away from someone else. It's a stretch and I wouldn't use it.