I wouldn't really mind the pressure and diameter limitations of BS7159. I have no bad experience using that code above 10 bar. You must always be cautious though of you reach the thin/thick walled pipe border. But that's for all piping.
I wouldn't use values from another vendor. Characteristics of the pipe are based on the base materials used and the winding angle (mainly, also other issues have an effect on the properties). Also most vendors have their own definitions for the different characteristics. Some already have an extra safety factor, some don't, some give the actual poisson ratio, some give the poisson ratio * Eh/Ea as needed for CAESAR II. You must have good knowledge about the material and production methods if you want to copy material properties between vendors, even between different series from the same vendor.