Well i live just down the road from you and was in that position a couple of years ago.(Now 18 and just finished A-levels) I did a lot of work into finding companies that would give me some work experience. A couple were helpful, although most just said they did not have any work experience available. Although i took up work experience with a computer company a friend of mine did some with honeywell in bracknell. He throughly enjoyed it and said he learned a lot! I'm affraid i can't give you any details as i don't have them to hand. But do definately get in contact with them, they may be able to help.
Expedite.