a law degree also gives you waaay more flexibility as well
as for joint honours, might give you that insight you need though to help you make an informed decision?
Then, do a more specialised Masters degree after that if necessary.
Psychology is not as useful as it sounds. To work as a Psychologist you need futher qualifications / PhD - many school leavers don't realise this, and there are not enough 'other' job oppotunies to absorb all the Psych grads that Unis are now churning out.
Law is more useful. There are a wide variety of different ares of Law to specialise in - and Law is also a good training for a host of other career areas. Corporate Law is a specilsm within Law practice, and you dont need a Business or Management degree to do it. This is the sort of postgrad Law Masters degree you would do after an LLB to enter this field : https://www.sheffield.ac.uk/postgrad...ercial-law-llm
The main problem with doing LLB Law as a joint subject is that you will only do half the Law degree - the other slots on your timetable with be 'the other subject', and you'll only do half of that. So it isnt as useful as a full Law degree - and many students find it very frustrating - their Law interests develop but they can't do the specialist units that are on offer to other students of the main Law pathway.
If you can, look for extras you can add to an LLB degree like a year abroad or a work placement - these do really add to your degree rather than taking away from it. Examples - https://www.bristol.ac.uk/study/unde...-study-abroad/ or https://www.exeter.ac.uk/undergradua...law_placement/