Custom voice pack - waze won't use the custom 'start' voices?

[zzyzxuk]

I've been using the Shizbox custom voice for a few years. I then went to the USA for a holiday, changed to a different voicpack and then changed it back to Shizbox - but now when I do, Waze won't use the StartDrivex.mp3 files from the voicepacks and only uses the 'default voice' files.... When I look at the voicepack in the waze app though, it still has the correct .mp3 files there for the startdrive commands - it just won't actually use them any longer...

Tried changing the custom voice as suggested as a fix for an issue with Android phones (my phone's an iphone), but this hasn't helped... Also tried reinstalling the voicepack, but Waze still won't use the StartDrive.mp3 files - just the other ones...

Any ideas?