Timezone changing in MacOS Catalina

I having a problem with timezones on my Macbook Pro, running MacOS Catalina 10.15.7.

I have recently moved countries, and since the move the location on the computer jumps between my current location (NZ) and my old location (UK). This affects the timezones, and various other things that make everything much harder.

I don’t really care about the location, but for some reason it always changes the timezone – regradless of whether timezone is linked to location or I manually set the timezone.

My suspicion is that this relates to some software installed on my computer by my employers (still in the UK), which is inadvertently resetting the timezone on my computer.

Is there something I can do to figure out what is triggering the location and/or timezone change on my computer?