i don't know much about lancaster but i am at leicester doing CS. overall, i think it's pretty good! i will say that there are definitely better unis for CS but it's still a great degree at a very reputable uni. the school of informatics oversees the CS-related degrees, it's an alright department but we have had some lecturers leave to go to better unis. some lecturers are great, some not so much - pretty typical. good range of course content and modules imo.
i think a degree in CS with a year's worth of industrial experience would do far more for you than a degree in data science, but i also don't know much about data science so take this with a grain of salt.
if you have any questions regarding literally anything about CS at leicester or just leicester itself, let me know!