Hi Alpha 5.
Hope you don't mind me pitching in here; I'm 2nd year BBA and currently on my first placement so just putting my two penneth in.
I think that you should aim high and go for front office at a top tier bank if that's what you wish - but I would NOT expect this in your first year by any means. There are many positions available that banks reserve for Bath BBAers for your first placement, but I think I can say accurately that these are all going to be back or middle office.
Haven't got to my second placement so not entirely sure, but I believe there will be more roles similar to front office, trading etc the second time round.
However, I would stress that either type of placement is difficult to get as this is obviously what the majority of students want. Getting a placement in general is VERY competitive and the placements office do not offer a panacea; the onus is very much on you. If you want a trading role, be prepared to really justify why.
I'm sure you know all this already, and sorry if it's unsolicited advice! I just found the whole placements thing a very different experience to what you would expect.
If you only listen to one thing I've said, let it be this - the most important thing to remember is that it is entirely what you make of it. Seek out your own opportunities, not just those advertised.
Good luck with your applications, I can't recommend Bath enough and in particular BBA, so go for it