I'm no longer in the life of dealing, but fentanyl, Hydromorphone and Oxymorphone where not the easiest to get your hands on towards the end of my days selling however fentanyl was quite easy to obtain illicitly where as in the early days most of it was coming from a pharmacy through some means. Even the oxys 80s both formulas since change of course, in my time where all pharmas and in unbelievable quantities. This country is corrupt and dodgy as fuck.
As for PCP that's a whole new level of fucking hard to get, tried it only once in my life and its so elusive the only way I know to get it is to smuggle it and run the risk your self or get someone to. To synthesis it here is possible but damn unlikely, further more straight up when you step into the right circles the gates open and the flood comes. However unlike America for example we are far more under wraps in a sense with our use and those who don't, are so oblivious to the sheer large amount that do use these drugs they'd never even expect, such as co workers, family members and so fourth and the amount that are privy to this and don't take part in that life but just are cool with it, might just blow your mind. The whole culture here is very different.
Other than that all I can say is go get a script if its legal. Not saying that will be easy, but from experience it is very possible. Honestly given the circle and right people you'll get your hands on just about almost anything.