Oggie
I can only recount my own experience. Roman Catholics did not have their own churchyards originally, so had to arrange to be buried somewhere! My London RC ggggrandparents, who died in 1834 and 1846, were buried in Old St Pancras churchyard, where apparently a lot of RC people were buried. I think I was told at one time that such burials would have taken place after dark. But they were entered in the St Pancras parish register, because a researcher found them there for me.
Sadly, there is no sign of their headstones in the churchyard.
MarieC