It wasn't until 1874 that it became compulsory to register deaths (and births, marriages).
So there may not be a death certificate! 
Registration of marriages has been compulsory since 1837, the act of 1874 refers to compulsory registration of births and deaths.
I have two deaths in my tree that don't appear to be registered, no record at the GRO or the local RO's.
Have you seen the entry in the PR for the burial, does it give a different abode to Skelton.
I have a burial at Skelton where the abode is listed as Darlington, Co Durham and that is where the death was registered.
Cheers
Jay