I am a law student at Coventry University, and I can confirm that not all universities require you to have completed a LNAT to study law. In fact, I myself did not complete the LNAT, and still managed to receive an offer to study law and here I am.
I believe these are the following universities that require the applicant to have completed a LNAT, however you may have to double check:
University of Bristol
University of Cambridge
University of Glasgow
King’s College, London (KCL)
London School of Economics and Political Science (LSE)
University of Oxford
University College London (UCL)
SOAS University of London
Singapore University of Social Sciences (SUSS), Singapore
IE School of Law, Spain
If you are not aiming for these universities then great. I can assure you there are many wonderful universities out there such as Coventry University, which does not require the applicant to have completed a LNAT yet will still offer you to study law.
Furthermore, you also mentioned that your subject choices are poor. In my opinion, as long as you know how to write an essay and develop the skill to write an essay or long pieces of writing in either of your subjects, that's good enough. However to really stand out, you could try to complete work experience at your local law firms, or simply just work shadow to get an idea of what it is like to work at a law firm. You could then input these experiences you have gained into you personal statement and explain why you are passionate about studying law at university (just make sure not to sound too cliche).
If you do not have time to complete work experience, I would at least recommend you to network by attending various events, hosted by law firms or universities etc. To begin the process of networking, you could create a LinkedIn account. This would be one of the best platforms to network and connect with lawyers (barristers or solicitors or even paralegals etc) or any other employers and industries.
Here are a few websites I recommend to you: ratemyplacement, brightnetwork, eventbrite, legalcheek, University Of Law. (To find placements and events)
Additionally, if you are worried about your subject choices (A-level or GCSE), I highly recommend speaking to your teachers, either your form teacher or head of year etc. AND it would be very ideal if you attended university open days, as you'll be able to speak to students and lecturers, as well as the admissions team, where you could discuss with them all about your subject choices too.
I really hope this helps.
Coventry University Student Ambassador