Oblivion station and video audio is stock audio - the rest was done by Tussauds.
There used to be a few of us, myself included, who would hunt audio down and email Tussaud’s Studios’ then audio department or the parks themselves.
Sometimes it was luck of the staff member you spoke to with some being more helpful than others.
Some were released samples like Hocus Pocus Hall - the audio doing the rounds of that is only a sample of the entire track and you can hear the abrupt cut off.
Bernie was the main individual from TS audio who was absolutely lovely in terms of helping and sending out samples but I know he had a lot of people email in!
Sometimes staff would take SD cards home overnight to rip audio and share with others or they would know someone in technical services who could obtain it for them.
However, there was a lot of hierarchy and ganging up on who had what audio and so sometimes it wasn’t the nicest of missions or “arm of the community” to be in.
Sadly, in 2007 Merlin shut down the audio department and it was outsourced entirely to companies/composers which I won’t bore you with listing here!
There was also the big audio leak - it allowed many to enjoy a lot of tracks as explained in posts above which is excellent but, in turn, made Merlin crack down. However, it did kill off the weird power games between audio people but sadly also killed off the audio community in a way.
The company then became reluctant to engage with audio until more recently when IMAScore engaged in the first talks to bring an Alton Towers Soundtrack and then a Thorpe Park one. Since then, merchandising teams have seen more of want for these and now we have streaming for the two parks. We’ve also seen bits released for Alton and Chessington by Simon Allen on YouTube.
However, it’s still a mission with all parks in regards to certain audio and I mean, anything from Legoland and Chessington is an uphill struggle…even if the composer is on board. it sadly comes down to management but also, they can’t just shove anything on streaming as there’s lots of hoops to jump through.
Stuff is out there but sadly the audio side of the community seems to be long dead and gone which is a huge shame and so it’s near on impossible to search and find.
EDIT: Just to add to the above about recording…yes I have some very dodgy recordings from years gone by but in American parks it’s not uncommon for people to do what we call induction recordings using an induction mic and setup - basically gives you a mono soundtrack-like track with no wind, mechanical/other sounds or talking etc