I am a happy rabbit owner in Corby, Northants.
The final decision in Corby's case to stop pet posts was not influenced by any animal rehoming emails (although the issue had been under debate for some time - I had never been entirely comfortable with FreeCycle as a medium for rehoming) but due to a problem with rehoming of a Staffordshire dog.
I still believe though that the majority of pet owners that use FreeCycle to rehome pets are responsible - the really irresponsible people just dump their pets without any attempt to find proper homes.
If you want to send any animal rehoming links ot the corbyUkfreecycle owner address then they will happily add to the links section.