Which finance internships to target?

I am a foreigner in an economics program now and looking for a summer internship in the UK. I decided to target BBs and a few other large banks because I figure for a work permit the smaller shops won't do.

Here is my key question--is it easier to get BB offers doing back office work (I'm thinking risk here) than the straight-up Investment Banking internship?

I am looking to move to the UK eventually. So I have to weigh my career goal, which ideally would be front office IB, and just getting whatever as long as a work permit is attached.

My thought is that back office is probably easier to get, so to be safe, I should apply to a good number of risk internships for next summer, and then work on getting a real IB internship off-cycle if possible. On the other hand, this would not make sense if there is no difference in difficulty between the BB risk and IB internships. Is there? Or does it depend on background? Thanks.