These padlocks always seem to go for such extreme amounts, and yet they do seem to come up often enough that if you really want one, you will get a chance, if you dig deep enough into your pocket. To make things worse, there are a couple different models if you look at all the Cotterill padlocks I have cataloged over the years.
This padlock had a high bid of 433 British Pounds/$678 (Plus 10 Pounds Shipping).Very rare 19thC Edwin Cotterill padlock with original key. Five inches high and weighing nearly one kg.It is in excellent working order and good condition for its age. The number 37077 is stamped on the front of the lock and also on the key.The escutcheon is held in place by a small button at the bottom of the keyhole. The end of the key is used to depress the button in order to move the escutcheon and allow access to the keyhole. - eBay (30 Jan 2012)