Hey
Both the fields that you have mentioned are great in terms of scope , but data science is a better evolving field . Learning skills in the field of data science alongwith knowledge of computer science can help you get a job with handsome package. If we predict on the estimated data , there will be more vacancies in the field of data science as in the upcoming times , there will be a lot data to  manage and interpret while computer science has its own never ending scope. You can even get a better salary in the field of data science in UK.