I totally get what you mean. There are some songs that are better speeded but generally those are rock songs... this one probably doesn't work as well as it could at that speed, which is a shame cos as you say Jaqui's voice makes the song
I know when I used to play live in front of much smaller crowds than this you get that adrenaline and everyone plays faster, but you don't always realise you're doing it in the heat of the moment.