I have seen some Youtube videos where the fuel rail has a "tyre valve" on one end for checking fuel pressure. My XC70 only has a torx screw in the end opposite the fuel pressure sensor. How can I test for correct fuel pressure after the car has been standing for a while?

I'm just trying to determine whether I need a new fuel pump or not. Sometimes my car will crank quite a while before it starts. Once it starts it's fine. I've replaced plugs, coils, fuel pressure sensor and injectors. Just trying to get to work out what's going on before attempting the huge job of replacing the fuel pump - which may not even achieve anything.