(I'm not even 100% percent sure if this is Konsole's issue, but here we go anyway)

I've got Konsole set up to send me a notification when the bell rings. That all works very nicely, except that if the bell rings 20 times, I'll get 20 notifications popping up (quite annoying). So, is there any way to set things up so that I get a maximum of one notification, regardless of how many times the bell rings?

I can confirm this is an issue in Konsole. Unfortunately the code controlling Bell notifications has no limits placed on it - unlike the activity notification code, which is limited to one notification each 15 seconds.