I did a quick Google search on mannequins from that period. According to Wikipedia life size wickerwork mannequins/dressforms came into use in the mid 18th century, and wire-work versions were made in Paris from 1835. I didn't come across any pictures from that era - more digging required!
Interesting article. Funnily enough I contacted Figure Forms a while back to ask about availability in the UK. Sadly not, and the shipping was very, very expensive. So I envy you having them at the bottom of the garden :D
I have an antique from about 1890 and one of the CLM ones for corsetry. I also made a couple myself using one of the AS patterns (the waspy one) I made it from coutil the way one would normally make a tailors ham, and now I have a corset shaped tailors ham to roll pin and steam mould onto. Possibly the best idea I have ever had :)