Dear Raspberry,
I am not aware if there is a standard named BS PD 8010. It's either BS 8010 (which is suppressed by BS EN 14161) or PD 8010. There is also no BS 8010 part 4.
@JT100: As far as my standards show, BS 8010 part 1 & 2 are for pipelines on land and part 3 for subsea. I think you are referring to PD 8010-2, Code of practice for pipelines Part 2: Subsea pipelines.
To conclude, if your project allows for the suppressed BS 8010 then decide the proper standard part based on where you are, on land or subsea. Otherwise, I suggest BS EN 14161.