I do not know London well enough to answer this, however I have ordered a toy or two from Sam (Tesselate) at tessletoys. perhaps you could look there for ideas.
Sculptors generally, but not exclusively, sculpt in clay or wax. A mould is then be made of this work according to which material the final piece will be cast in. Bronze or foundry bronze pieces are made using hot metal which is poured into the mould...
What country are you in? In Ireland there was a tax funded program that established many outdoor sculptures of value (and, of course, some of no value). Yet there were no funds to publicize their location, so one came upon them by accident usually. I...