Apparently the UK theatrical release featured several cuts, particularly around the scenes where the priest extracts the heart from the sacrificial victim, and when he subsequently bursts into flames in the pit, and also where the guard gets caught in the grindstone.
I am happy to report that the R1 and R4 versions of the film appear to be identical, based on a frame by frame comparison between the R1 and the R4 on three critical scenes (Chapter 18: The Temple Of Doom, Chapter 21: The Blood of Kali and Chapter 22: Willie's Sacrifice). Therefore the version presented is not the UK censored version.