Before I buy one, can anyone tell me if they work or not, or give any tips on using one successfully, please?

Yes they do work. Put any compostable material in them. Don't put too much grass in though, it won't work properly. Leaves, potato peelings, weeds, flowers, put them in. Just leave it for a few months and it will rot down good enough to dig in the garden.

Yes they do work. Worm compost bins work faster. Try this site www.wormsdirectuk.co.uk Worms dont like certain things and meat and bones arent a good idea as it encourages rats.

Yes, they work - but so does throwing the stuff in a heap. If you turn it, it will "cook" faster, but even if you simply drop everything on the pile, you will still get compost...it'll just take a little longer.