Ah, Colin, you have what is known in my house as the 'Drumming Bear' syndrome
Quick explanation:
When my son was very small, he had a drum playing plastic bear that we used to wind up and one day it failed, over to Dad to fix. So, 18 years later bits of bear are still in the box, main spring sprung..never to be seen again..but, on a more serious note,
How about the clicky top biro pens, there are springs in them; and by hey there are some 'howking geet' big springs in an automatic washer and aye, I could tell you a good story about them too.
As previously mentioned I have also dismantled an old cassette player that I thought my son had finished with, to use some of the springs and pulleys in there.
aye
john e
bluebird
ps my son doesnt know about the cassette player yet