have you studied law for four years and now plan on beginning a degree in architecture from scratch? (just to verify)
law is a part of architectural degree courses. contract law, the incredible subtleties of offers and invitations to treat, and whatever else one needs to know to realise that you need to hire a lawyer to cover your ass. i dont think a background in law would help much in progressing through architecture, but if you did choose to work as an architect then a background in law would be a great asset. in the real world of big bad people, architecture becomes more of a business than an art-form.
i myself will soon complete my degree, and am considering doing follow on courses in structural engineering, business, and law, so as to make myself not only more employable, but also more capable of starting a firm of my own, which i think is the aspiration of most architecture students.
also clmoll-curious square, i think the fact that you've survived four years of law would make the study of architecture easier for you. if you have a strong work ethic, like to and are able to read and study journals and literature as it comes out, and if you are able to bullshit your way around lecturers like barristers are able to around the court system (400 quid an hour i heard once from an unreliable source) then i think you'd do fine.
just as a point of interest, what made you decide to change your career path so dramatically? and are you qualified in law?
whatever you decide, good luck.