I did my work experience at woolworths lolcat. It wasn't bad, it will probably boost your confidence for getting a job later on. And yeah some places did pay people on work experience, I didn't get payed though
Sadly, I hear that its mostly business-type of work that pays. Life is so unfair sometimes

---------- Post added at 10:58 PM ---------- Previous post was at 10:52 PM ----------
I'm from UK as well, I'm in year 11 and I did my work experience last year. The most important thing is PICK YOUR OWN PLACEMENT !!!! I didn't pick mine and so the people who run work experience choose a placement for you based around what you would like and what are you would like it to be in. I got put in Boots on a high street and it was complete and utter 5#!T. I had to read like 8 books on how on health and safety like, how to pick up boxes without injuring yourself, what fire extinguisher to use for certain fires, etc. The manager then made me walk around for an hour mesmerizing the whole store so that I could tell a customer where everything was. After mesmerizing the whole store floor. He then put me in the back room and made me sort out the whole stock cupboard into alphabetical order, once I had done that he made me stack shelves with the things I had just sorted out which he then made me do for the next two days, just stack shelves :|... I then started turning up like two hours late because it was 5#!T xD and leaving at lunch lol... The next day I come in and he started having a go at me and then I got sacked lol which was actually pretty funny because he literally started shouting at me from point blank and I started laughing so I got sacked. After the two weeks of work experience ,where I only done 3 days and played COD for the rest, everybody who chose their own placement like paintballing, beauty shops, gyms, kids kingdom, bowling all seemed to have had a pretty good time. You MUST MUST MUST choose your own placement !! Most people that did well and had nice managers and staff got paid, or got presents, or offered Saturday / Full-Time jobs for when we leave.
I bet Boots was shit lol. And I was going to pick what I wanted to do for myself. I don't let shit tell me what I do. I might do a bit of building work for my work experience. There's a whole estate being built just over the road from my house, so if I can, I might go there. I'm not looking forward to the cheesy 80's music and builder's crack's though. I'd still rather do that, than work in Boots, or any other business-type of work.