Well, hopefully they weren't the ones ringing the bell. During these times, it sometimes happened that someone had appeared dead but was not and thus they were buried alive. When the people realized what they had done, they began to attach a bell above the graves and ran a string to the corpse. If by chance they came out of their coma or whatever it was that made them appear as though dead, they would ring the bell. Perhaps there was another bell rung from the church, but let's hope the Knells were not ringing these.
As far as John ringing bells, it would have to have been a hobby above and beyond his regular duties as he was a weaver who was most likely one of many who emigrated from Dorset-shire (known for its sheep).