Hi, I usually do US Styled sirens but i wanted a littl change so i made a uk siren, hope you enjoy, if you dont know how to install;
x64-audio-sfx-resident.rpf drag the folder and the file onto your desktop TOGETHER and drag and drop the .oac into resident.rpf

https://www.youtube.com/watch?v=YuXTLhjwPmY&t=19s