Samosas are on your way via email.
I did AS and A level Psychology. I only took it because it was fun and easy (for me at least). It's actually kinda weird because the degree I'm doing, business and marketing, did not require me to take psychology at all.
You can still do a law at degree level without psychology, or any degree, provided of course you have the UCAS points required by the univeristy you've chosen to take your degree at. This is usually around 200 plus points, which roughly equates to 2 C's (80 + 80) and an E (40) minimum. Which is pretty easy actually. Don't worry too much about messing up in psychology - even if you get an E in it, your ucas points should still be high enough to get into uni, so you'll still be able to take your law degree.
p.s; If you want to pursue a career in a certain subject area, I would highly recommend taking a degree in it. i.e. if you wanted to be a lawyer, it'd make sense to take a law degree.