That UR-CGW is a busy lad. Currently droning westbound across Lincolnshire at 21000...
Yep, the Dart's sound was pretty distinctive, my mind can still hear BIA Heralds starting and taxying at Gatwick, also 1-11s had a pretty distinctive start up sound.
If you really want a good turboprop sound though, the AN-22 is hard to beat in this day and age - probably the Tu-95 as well.