I know from sad personal experience that Australian PAL differs from UK/European PAL.

I brought my nice colour TV with me when I came to Australia, because I checked things out and both countries use PAL.

However, the sound is encoded differently in Australia (less efficiently - there is a noticeable feedback effect between sudden changes of screen intensity, and volume which is deliberately exploited by advertisers to make your TV blast lumps of sound at you during Ads!)

Also, the Uk has been on UHF (625 lines) for a long time now, while Australia is still stuck mostly on VHF.

So as a consequence of all the above I have a large desktop ornament that can receive only 1 out of 5 free-to-air channels, and doesn't have sound

(and it doesn't work through an Australian VCR, either!)