The story is found here. it appears that the Vicar has been quoted as saying there is such a thing as an exemption certificate but as far as I can ascertain this does not exist under law. If the liability is derived from an enclosure award as would seem to be the case an exemption certificate may prevent the parish from asking for money from one lay rector but other lay rectors who did not take out the certificate would be given a heavier bill or still have the right to claim from those who took out the certificate.
The only legal way to rid a plot of land from the liability is under the 1923 Ecclesiastical Dilapidations Measure with a certificate issued by the Diocesan authority. Any other means of doing it may be unsuccessful or put the PCC into legal hot water for failing to protect the other lay rectors interests.