The automatic warning system (AWS) has a tendency to show the sunflower symbol as it should, but not play its sound accordingly. This doesn't happen every single time the AWS goes off, however it is worth addressing as on two occasions I've had brake demand with no audible warning. This could apply to other AWS-fitted trains, though I cannot be certain as such.
I have found that too. It seems to improve if you set everything else up first and then put safety systems on. If you have tried that already then apologies, but hope it helps.
My additional observation is when the bell does sound, it is very quiet, nearly drowned out by the ambient cab noise. I often miss it
