This is ridiculous...
Take what you need to get where you want to be. As
@999tigger mentions, Law has no specific requirements, a D* would count as an A* and a D (Distinction) would count as an A towards the grade requirements for the vast majority of universities, regardless of the subject the BTEC is in.
I don't know why you feel "stupid" taking BTECs? I did a BTEC Extended Diploma (without any A levels) and I graduated from a top 30 uni last year and recently completed a Masters at a top 10 for my subject (Computer Science). Pretty much every uni will accept BTEC, with the exception of Imperial and some Scottish unis.