(Posted in 2 Parts):
Check this link for details of careers as a DJ:
http://www.learndirect-advice.co.uk/helpwithyourcareer/j obprofiles/profiles/profile780/
This is the one for work as a radio presenter:
http://www.learndirect-advice.co.uk/helpwithyourcareer/j obprofiles/profiles/profile780/
This gives details of working as a production assistant:
http://www.learndirect-advice.co.uk/helpwithyourcareer/j obprofiles/profiles/profile980/
As Tony has indicated, hospital radio is often the first step in the career path for many DJ's and presenters. Some people move on from hospital broadcasting to part-time work for the BBC (often for very small payments). For example, most of the evening and late-night broadcasters on BBC local radio are part-time freelancers. (Many of them are schoolteachers during the day).
Sometimes you just need to find a way to prove that you've got broadcasting skills. (A teaching colleague of mine used to present a local radio show on Sunday afternoons. When he couldn't be present for a couple of Sundays he asked if I could fill in. From then on I was always on the 'relief' team for that station. Later, when I'd moved to the other side of the country, I did an interview on a BBC local station about plans for a new museum. The presenter was so impressed with the interview that I was asked to co-host his Sunday show (on an 'expenses only' basis -typical BBC!) Unfortunately, due to other commitments, I couldn't take up the offer but it shows that the first thing to do if you want to work in radio