Is there anything wrong with this combination?

hey, the first thing is I'm assuming you're an AS student. Most people take four so you might want to take another one (Have you looked at maths? You use it a lot in chemistry and although I haven't looked at any of those specific degrees I'm fairly certain unis would prefer it if you did maths- although don't do something you hate.)
I don't think it's an odd combination. Unusual maybe but not odd and I know quite a few people who took 2 science subjects and another completely different one (The most unusual being maths chemistry and art). I did the same.
It's still important to say that- if you do want to do law- most places paradoxically prefer you not to have taken law (don't ask me why) and many places don't consider it as "respected". That doesn't mean its automatically a bad idea and asyou're already doing chemistry and biology I highly doubt they'd be too concerned. As you asked it probably doesnt matter and if its something you really want to do then go for it.
One last thing. I took OCR biology AS. It's pretty much all plants- SO BORING

Thank you for your reply! Well, I'm about to start in September, and because of the new linear course structure, I'm unable to drop anything to an AS level. So if I choose 4, I have to stick with 4 or drop 1 entirely. So it's a huge pain! Yeah I was considering doing maths or physics as a fourth. Or maybe history, so I can pair that with law and pair chemistry with biology. I'm drifting more towards maths or physics though I think.

I don't think I'll pursue Law any further after A level. It's unlikely I will. I wanted to do it because I think I'd do well in it and look more appealing to universities when applying.

So yes, thank you. And about the biology, I'm dreading the plants! Although if I really hated it I probably wouldn't do biology, as I was told that a generous amount of it would be plant based. Was it difficult for you at all, may I ask?

ahhhh that's odd. Sucks. I took chemistry biology maths and history at AS intending to drop history. Ended up hating biology and taking the other 3 to A2 (along with an extra AS in further maths). I couldn't of done that if it wasn't for the AS exams. (If you have any specific questions about the subjects please feel free to ask). Kinda why I think its a good idea not to specialise- you can always change your mind (Maybe thats just me)
As for maths or physics there's a which guide you can find online which shows you the a-level subjects preferred for different degrees here http://university.which.co.uk/advice/a-level-choices/what-a-levels-do-you-need-for-the-degree-you-want-to-study and I think there's another one displaying how many university students have an a level by subject.
As for biology. Not going to lie I hated it. There were specific sections such as the heart/liver etc which weren't so bad but on the whole it was just well boring. While there is an exorbitant amount of memorisation and the mark schemes were always somewhat pedantic those with a good memory tended to do ok (I disliked it more than most). One thing I remember was if you got stuck you could just write the word "diffusion" and you'd be likely to get an extra mark. When you start I'd make a lot of revision posters etc and just look at them continually to try and help you memorise the content.
Good luck with your a levels

ahhh don't worry about comparing the difficulty- there was this huge section on exology that was pretty much exactly the same (And from what I've heard the A2 section is pretty similar too).
A level maths is mostly practice. If you've come in with a slightly weaker grade I would get a study buddy and make sure to ask for help as soon as you need it/ go to surgery etc. That being said I've seen people pick up a couple of grades in it from AS-A2 (My college didn't allow you to take it with less than an A) but at the same time people would go from an A* at GCSE to a U at AS. GCSEs aren't necessarily an accurate grade predictor.
Well done on the A* though!
I am planning on going to uni although what to study and when I'm still undecided (I have a place for maths this year but don't know if I'm going to take it. You can check my other threads if you want more detais but it's really not that interesting)
Everyone doubts their ability at on point. But at the same time it gives you an opportunity to prove yourself wrong i guess?