UCAS allows different course titles
Universities do not require every course title on your UCAS application to be identical. You can apply for different course names at different universities.
That freedom is mainly useful because universities do not label courses in exactly the same way. One university may call a course English, another may call it English Literature, and another may use a title that reflects a particular pathway or optional specialism. The title has changed, but the academic case behind the application remains the same.
A strong UCAS application has one clear academic direction. It should look as though you know what you want to study, even if the course titles vary slightly between universities.
One personal statement has to support every choice
Your personal statement is sent to all of your UCAS choices.
That creates the real limit on how different your courses can be. The UCAS form may let you apply for unrelated subjects, but the personal statement still has to persuade each university that you are suited to its course.
A statement written for English Literature should show reading, interpretation, argument and engagement with literary ideas. If the same statement is also trying to support an application for Business Management, it will not have enough space to make either case properly. The application starts to look uncertain rather than broad.
This is why different course titles are safest when they are really naming differences, not substantial course differences.
Similar names still need checking
Course titles can be misleading, so do not rely on the name alone.
Two courses with similar titles can have different first-year modules, different methods, different assessment styles and different expectations. Before treating two courses as close enough for one application, read the course pages carefully. Look at the required subjects, the compulsory modules and the kind of academic work the course appears to emphasise.
If the same personal statement can genuinely support both courses, the difference is manageable. If one course would need a different explanation of your interests, preparation and evidence, it does not belong in the same application.
Do not use one application for two academic directions
Applying for substantially different courses is allowed by UCAS, but it is poor application strategy.
A student who is still choosing between two unrelated subjects should resolve that decision before applying. The personal statement cannot cover two separate academic directions well. It either becomes vague enough to fit everything, or split enough to satisfy nobody.