Hi Yanis,
Welcome to IceInSpace
Whereas you don't need prior permission to turn up to an organised observing session at the Pony Club, it is always a good idea to check this forum that some are going to be there that night.
You see, there is a locked gate and only a few with keys. (Myself included).
Most people turn up around sunset, to set up scopes etc in the light (or twilight).
Lately, we have had some heavy dew later in the nights at the PC, and it is not uncommon for everyone to have packed up and gone home well before 2am (sometimes even before midnight!).
So I cannot guarantee that someone will still be there if you turn up at that time.
Anyway, keep an eye on this thread and take it from there.
Hope to see you Saturday.