Depending on your age there are many options open to you, if you are under 19 then I would highly recommend that you go to college and complete either A-Levels or BTEC qualifications, this is because they are a much broader base for you. For example, if you change your mind in the future about what you want to study or what you want to be as a professional, then qualifications like A-Levels and BTECs leave more doors open.
You could also try apprenticeships, however, securing one in a legal field could be very very difficult.
If you are over 19, then you have many options, the best would be to complete an Access to HE course, as a previous commenter has stated, be sure that you Email chosen universities first with a link to the specific access course, so that they can confirm that they will accept it. You can do Access courses in Law, Law & Criminology, Law & Politics etc. and they are all great to get you ready for university, especially if you are not so academically inclined as they include study skill modules.
Then there is the pathway of more vocational qualifications such as NVQ’s, however again, legal subjects are not really covered by this, but you could perhaps find relevant areas that would be useful as a legal professional.
You also have professional experience entry, some universities will allow you entry on a course if you have relevant work experience, but again like many of the previous options, getting relevant work experience in a law field is insanely hard.
As you mentioned foundation years are also a possibility, but you should be prepared that most universities still want you to have some A-Levels or BTEC qualifications to get on a foundation course (they are just lower than the base course)
Your best bet is to stick to either A-Levels/BTECs or if over 19 go down the Access course route.
Right now, with just the GCSE’s you have stated, I can’t see you getting onto a LLB, unless it was with a ‘bad’ university, as you said you wish to be a Barrister then you are going to need to go to a top university and graduate with a first degree to even be considered for the BPTC let alone a pupillage.
My best advice is to research law, research the careers, research JUST how hard it is to be a barrister (there are only 15,000 in the entire UK), research what is needed and what is expected. Because law is not what it is on TV, go to your local courts and spend a few days watching cases and seeing how real life trials really work. Law is 90% paperwork and reading and research and stereotypically ‘boring’ things, it is monotonous and draining and SO confusing and often does not follow common sense or logic…
If reading all of this has not put you off, then go for it! Just know it is a challenge, but never ever let anybody tell you that you cannot do It, or that you should not do it! If it is what you want, if it is what you can really see yourself doing, then try your best and just go for it 😊 Another bit of advice for you is to go to university open days (even if they are unis you don’t want to go to), because you can experience law lectures and truly see what it is like learning law, they also offer ‘taster days’ where you spend the day as a law student. Just spend about a week researching the legal field and what it’s like learning law; it isn’t a subject to just jump into because ‘why not’ or ‘it looks fun’, you should really know what it is that you are getting into
I wish you the best of luck 😊