Don't bother with brakes for a long time yet, I've been riding Muni 4 years and I've only just felt the need to get brakes. For £165 you can get the Nimbus II 24" Muni, it's good for muni, you can do some trials on it and it's good enough for getting around. For a little more you could get the Qu-Ax which has a splined hub and will therefore with stand larger drops with out breaking. If you can I'd go for that, it will last much longer and be cheaper in the long run,they're £185.
Why do people always reply to these threads by suggesting bying the most expensive and up-to-date uni, even if the person is a beginner and has said they can't spend much?