I also really enjoyed this show and rewatched it a few years ago on DVD. But I certainly noticed the main title music was different. I don't recall noticing in-episode music though, and wouldn't have remembered it from the show.

I went looking for the PAL DVDs after seeing your comment, and found one season but not a full set. After looking a little online it seems like the PAL release might have been cropped down a bit from the NTSC release? If that's the case it seems pretty disappointing.